Toan_5

["1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh r : a) r = 5cm ; b) r = 0,4dm ; c) r = m. 2 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn c\u00e3 \u00ae\u00f0\u00eang k\u00ddnh d : a) d = 12cm ; b) d = 7,2dm ; c) d = m. 3 T\u00ddnh di\u00d6n t\u00ddch c\u00f1a m\u00e9t m\u00c6t b\u00b5n h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh 45cm. Luy\u00d6n t\u00cbp 1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh r : a) r = 6cm ; b) r = 0,35dm. 2 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn bi\u00d5t chu vi C = 6,28cm. 3 Mi\u00d6ng gi\u00d5ng n\u00f0\u00edc l\u00b5 m\u00e9t h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh 0,7m 0,3m 0,7m. Ng\u00f0\u00eai ta x\u00a9y th\u00b5nh gi\u00d5ng r\u00e9ng 0,3m bao quanh mi\u00d6ng gi\u00d5ng. T\u00ddnh di\u00d6n t\u00ddch c\u00f1a th\u00b5nh gi\u00d5ng \u00ae\u00e3. Luy\u00d6n t\u00cbp chung 7cm 10cm 1 M\u00e9t s\u00eei d\u00a9y th\u00d0p \u00ae\u00f0\u00eec u\u00e8n nh\u00f0 h\u00d7nh b\u00aan. T\u00ddnh \u00ae\u00e9 d\u00b5i c\u00f1a s\u00eei d\u00a9y. 15cm 60cm 2 Hai h\u00d7nh tr\u00dfn c\u00e3 c\u00efng t\u00a9m O nh\u00f0 h\u00d7nh b\u00aan. Chu vi h\u00d7nh tr\u00dfn l\u00edn d\u00b5i h\u00acn chu vi h\u00d7nh tr\u00dfn b\u00d0 O bao nhi\u00aau x\u00a8ng-ti-m\u00d0t ? 100","3 H\u00d7nh b\u00aan t\u00b9o b\u00ebi h\u00d7nh ch\u00f7 nh\u00cbt v\u00b5 hai n\u00f6a 10cm h\u00d7nh tr\u00dfn (xem h\u00d7nh v\u00cf). 7cm T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh \u00ae\u00e3. 4 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : A 8cm B O Di\u00d6n t\u00ddch ph\u00c7n \u00ae\u00b7 t\u00ab m\u00b5u c\u00f1a h\u00d7nh vu\u00abng ABCD l\u00b5 : DC A. 13,76cm2 B. 114,24cm2 C. 50,24cm2 D. 136,96cm2 Gi\u00edi thi\u00d6u bi\u00d3u \u00ae\u00e5 h\u00d7nh qu\u00b9t a) V\u00dd d\u00f4 1 : H\u00d7nh v\u00cf d\u00f0\u00edi \u00ae\u00a9y l\u00b5 bi\u00d3u \u00ae\u00e5 h\u00d7nh qu\u00b9t cho bi\u00d5t t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00b8c lo\u00b9i s\u00b8ch trong th\u00f0 vi\u00d6n c\u00f1a m\u00e9t tr\u00f0\u00eang ti\u00d3u h\u00e4c. Truy\u00d6n S\u00b8ch gi\u00b8o thi\u00d5u nhi khoa 25% 50% C\u00b8c lo\u00b9i s\u00b8ch kh\u00b8c Nh\u00d7n v\u00b5o bi\u00d3u \u00ae\u00e5 ta bi\u00d5t : \u2212 C\u00e3 50% s\u00e8 s\u00b8ch l\u00b5 truy\u00d6n thi\u00d5u nhi ; 25% \u2212 C\u00e3 25% s\u00e8 s\u00b8ch l\u00b5 s\u00b8ch gi\u00b8o khoa ; \u2212 C\u00e3 25% s\u00e8 s\u00b8ch l\u00b5 c\u00b8c lo\u00b9i s\u00b8ch kh\u00b8c. 101","b) V\u00dd d\u00f4 2 : Bi\u00d3u \u00ae\u00e5 h\u00d7nh qu\u00b9t b\u00aan cho bi\u00d5t t\u00d8 C\u00c7u l\u00abng B\u00aci s\u00e8 ph\u00c7n tr\u00a8m h\u00e4c sinh tham gia c\u00b8c m\u00abn 25% 12,5% th\u00d3 thao c\u00f1a l\u00edp 5C. Bi\u00d5t r\u00bbng l\u00edp 5C c\u00e3 32 h\u00e4c sinh, h\u00e1i c\u00e3 bao nhi\u00aau b\u00b9n tham gia C\u00ea vua m\u00abn B\u00aci ? 12,5% Nh\u00d7n v\u00b5o bi\u00d3u \u00ae\u00e5 ta th\u00cay c\u00e3 12,5% Nh\u00b6y d\u00a9y h\u00e4c sinh tham gia m\u00abn B\u00aci. 50% V\u00cby s\u00e8 h\u00e4c sinh tham gia m\u00abn B\u00aci l\u00b5 : 32 \u00d7 12,5 : 100 = 4 (h\u00e4c sinh) 1 K\u00d5t qu\u00b6 \u00aei\u00d2u tra v\u00d2 s\u00f9 \u00f0a th\u00ddch c\u00b8c lo\u00b9i Xanh 40% \u00a7\u00e1 25% m\u00b5u s\u00bec c\u00f1a 120 h\u00e4c sinh \u00ae\u00f0\u00eec cho tr\u00aan T\u00ddm 15% bi\u00d3u \u00ae\u00e5 h\u00d7nh qu\u00b9t b\u00aan. H\u00b7y cho bi\u00d5t c\u00e3 bao nhi\u00aau h\u00e4c sinh : Tr\u00beng 20% a) Th\u00ddch m\u00b5u xanh ? b) Th\u00ddch m\u00b5u \u00ae\u00e1 ? c) Th\u00ddch m\u00b5u tr\u00beng ? d) Th\u00ddch m\u00b5u t\u00ddm ? 2 Bi\u00d3u \u00ae\u00e5 d\u00f0\u00edi \u00ae\u00a9y n\u00e3i v\u00d2 k\u00d5t qu\u00b6 h\u00e4c t\u00cbp c\u00f1a h\u00e4c sinh \u00eb m\u00e9t tr\u00f0\u00eang ti\u00d3u h\u00e4c : H\u00e4c sinh gi\u00e1i 17,5% 22,5% H\u00e4c sinh kh\u00b8 60% H\u00e4c sinh trung b\u00d7nh H\u00b7y \u00ae\u00e4c t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a h\u00e4c sinh gi\u00e1i, h\u00e4c sinh kh\u00b8 v\u00b5 h\u00e4c sinh trung b\u00d7nh tr\u00aan bi\u00d3u \u00ae\u00e5. 102","luy\u00d6n t\u00cbp v\u00d2 t\u00ddnh di\u00d6n t\u00ddch V\u00dd d\u00f4 : T\u00ddnh di\u00d6n t\u00ddch c\u00f1a m\u00b6nh \u00ae\u00cat 20m c\u00e3 k\u00ddch th\u00f0\u00edc theo h\u00d7nh v\u00cf b\u00aan : 20m 40,1m 25m 25m 20m 20m Ta c\u00e3 th\u00d3 th\u00f9c hi\u00d6n nh\u00f0 sau : E 20m G a) Chia m\u00b6nh \u00ae\u00cat th\u00b5nh h\u00d7nh ch\u00f7 nh\u00cbt ABCD v\u00b5 hai h\u00d7nh vu\u00abng b\u00bbng 20m B nhau EGHK, MNPQ. A H b) T\u00ddnh : K \u00a7\u00e9 d\u00b5i c\u00b9nh DC l\u00b5 : 25m M 40,1m 25 + 20 + 25 = 70 (m) D Di\u00d6n t\u00ddch h\u00d7nh ch\u00f7 nh\u00cbt ABCD l\u00b5 : N 25m C 70 \u00d7 40,1 = 2807 (m2) Di\u00d6n t\u00ddch c\u00f1a hai h\u00d7nh vu\u00abng EGHK 20m v\u00b5 MNPQ l\u00b5 : Q 20m P 20 \u00d7 20 \u00d7 2 = 800 (m2) Di\u00d6n t\u00ddch m\u00b6nh \u00ae\u00cat l\u00b5 : 2807 + 800 = 3607 (m2 ) 103","1 T\u00ddnh di\u00d6n t\u00ddch c\u00f1a m\u00b6nh \u00ae\u00cat c\u00e3 k\u00ddch th\u00f0\u00edc 3,5m 3,5m theo h\u00d7nh v\u00cf b\u00aan. 3,5m 6,5m 4,2m 2 M\u00e9t khu \u00ae\u00cat c\u00e3 k\u00ddch th\u00f0\u00edc theo h\u00d7nh v\u00cf d\u00f0\u00edi \u00ae\u00a9y. T\u00ddnh di\u00d6n t\u00ddch khu \u00ae\u00cat \u00ae\u00e3. 40,5m 50m 50m 40,5m 30m 100,5m luy\u00d6n t\u00cbp v\u00d2 t\u00ddnh di\u00d6n t\u00ddch (ti\u00d5p theo) V\u00dd d\u00f4 : M\u00e9t m\u00b6nh \u00ae\u00cat c\u00e3 h\u00d7nh d\u00b9ng B C D nh\u00f0 h\u00d7nh b\u00aan. N \u00a7\u00d3 t\u00ddnh di\u00d6n t\u00ddch m\u00b6nh \u00ae\u00cat \u00ae\u00e3, ta c\u00e3 A th\u00d3 l\u00b5m nh\u00f0 sau : M E a) N\u00e8i \u00aei\u00d3m A v\u00edi \u00aei\u00d3m D, khi \u00ae\u00e3 m\u00b6nh \u00ae\u00cat \u00ae\u00f0\u00eec chia th\u00b5nh h\u00d7nh thang ABCD v\u00b5 h\u00d7nh tam gi\u00b8c ADE. K\u00ce c\u00b8c \u00aeo\u00b9n th\u00bcng BM, EN vu\u00abng g\u00e3c v\u00edi AD. 104","b) \u00a7o c\u00b8c kho\u00b6ng c\u00b8ch tr\u00aan m\u00c6t \u00ae\u00cat. Gi\u00b6 s\u00f6 ta c\u00e3 b\u00b6ng s\u00e8 li\u00d6u c\u00b8c k\u00d5t qu\u00b6 \u00aeo nh\u00f0 sau : \u00a7o\u00b9n th\u00bcng \u00a7\u00e9 d\u00b5i BC 30m AD 55m BM 22m EN 27m c) T\u00ddnh : H\u00d7nh Di\u00d6n t\u00ddch H\u00d7nh thang ABCD H\u00d7nh tam gi\u00b8c ADE H\u00d7nh ABCDE 935 + 742,5 = 1677,5 (m2) V\u00cby di\u00d6n t\u00ddch m\u00b6nh \u00ae\u00cat l\u00b5 1677,5m2. 1 T\u00ddnh di\u00d6n t\u00ddch m\u00b6nh \u00ae\u00cat c\u00e3 h\u00d7nh d\u00b9ng nh\u00f0 B h\u00d7nh v\u00cf d\u00f0\u00edi \u00ae\u00a9y, bi\u00d5t : E AD = 63m A GC AE= 84m D 105 BE= 28m GC = 30m.","2 T\u00ddnh di\u00d6n t\u00ddch m\u00b6nh \u00ae\u00cat c\u00e3 h\u00d7nh d\u00b9ng nh\u00f0 h\u00d7nh v\u00cf d\u00f0\u00edi \u00ae\u00a9y, bi\u00d5t : BM = 20,8m C CN = 38m B AM = 24,5m MN = 37,4m ND = 25,3m. A ND M Luy\u00d6n t\u00cbp chung v\u00b5 chi\u00d2u cao T\u00ddnh \u00ae\u00e9 d\u00b5i \u00ae\u00b8y c\u00f1a 1 Cho h\u00d7nh tam gi\u00b8c c\u00e3 di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c \u00ae\u00e3. 2 M\u00e9t chi\u00d5c kh\u00a8n tr\u00b6i b\u00b5n h\u00d7nh ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 2m v\u00b5 chi\u00d2u r\u00e9ng 1,5m. \u00eb gi\u00f7a kh\u00a8n ng\u00f0\u00eai ta th\u00aau ho\u00b9 ti\u00d5t trang tr\u00dd h\u00d7nh thoi c\u00e3 c\u00b8c \u00ae\u00f0\u00eang ch\u00d0o b\u00bbng chi\u00d2u d\u00b5i v\u00b5 chi\u00d2u r\u00e9ng c\u00f1a h\u00d7nh ch\u00f7 nh\u00cbt. T\u00ddnh di\u00d6n t\u00ddch kh\u00a8n tr\u00b6i b\u00b5n v\u00b5 di\u00d6n t\u00ddch h\u00d7nh thoi. 3 M\u00e9t s\u00eei d\u00a9y n\u00e8i hai b\u00b8nh xe r\u00dfng r\u00e4c (nh\u00f0 h\u00d7nh v\u00cf). \u00a7\u00f0\u00eang k\u00ddnh c\u00f1a b\u00b8nh xe c\u00e3 \u00ae\u00e9 d\u00b5i 0,35m. Hai tr\u00f4c c\u00b8ch nhau 3,1m. T\u00ddnh \u00ae\u00e9 d\u00b5i s\u00eei d\u00a9y. 3,1m 0,35m 106","H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt. H\u00d7nh l\u00cbp ph\u00f0\u00acng a) H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt Bao di\u00aam Vi\u00aan g\u00b9ch H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt Bao di\u00aam, vi\u00aan g\u00b9ch c\u00e3 d\u00b9ng h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt. H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 s\u00b8u m\u00c6t (nh\u00f0 h\u00d7nh v\u00cf) : hai m\u00c6t \u00ae\u00b8y (m\u00c6t 1 v\u00b5 m\u00c6t 2) v\u00b5 b\u00e8n m\u00c6t b\u00aan (m\u00c6t 3, m\u00c6t 4, m\u00c6t 5 v\u00b5 m\u00c6t 6) \u00ae\u00d2u l\u00b5 h\u00d7nh ch\u00f7 nh\u00cbt. M\u00c6t 1 b\u00bbng m\u00c6t 2 ; m\u00c6t 3 b\u00bbng m\u00c6t 5 ; m\u00c6t 4 b\u00bbng m\u00c6t 6. 1 1 5 1 3 64 5 6 34 56 34 2 2 2 H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt (h\u00d7nh b\u00aan) c\u00e3 : A B G T\u00b8m \u00ae\u00d8nh l\u00b5 : \u00ae\u00d8nh A, \u00ae\u00d8nh B, \u00ae\u00d8nh C, D C Chi\u00d2u cao \u00ae\u00d8nh D, \u00ae\u00d8nh M, \u00ae\u00d8nh N, \u00ae\u00d8nh P, \u00ae\u00d8nh Q. N G M\u00f0\u00eai hai c\u00b9nh l\u00b5 : c\u00b9nh AB, c\u00b9nh BC, M P Chi\u00d2u r\u00e9ng c\u00b9nh DC, c\u00b9nh AD, c\u00b9nh MN, c\u00b9nh NP, c\u00b9nh QP, c\u00b9nh MQ, c\u00b9nh AM, c\u00b9nh BN, Q Chi\u00d2u d\u00b5i c\u00b9nh CP, c\u00b9nh DQ. H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 ba k\u00ddch th\u00f0\u00edc : chi\u00d2u d\u00b5i, chi\u00d2u r\u00e9ng, chi\u00d2u cao. 107","b) H\u00d7nh l\u00cbp ph\u00f0\u00acng Ta c\u00f2ng th\u00f0\u00eang g\u00c6p trong th\u00f9c t\u00d5 m\u00e9t s\u00e8 \u00ae\u00e5 v\u00cbt nh\u00f0 con s\u00f3c s\u00bec c\u00e3 d\u00b9ng h\u00d7nh l\u00cbp ph\u00f0\u00acng. H\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 s\u00b8u m\u00c6t l\u00b5 c\u00b8c h\u00d7nh vu\u00abng b\u00bbng nhau. Con s\u00f3c s\u00bec H\u00d7nh l\u00cbp ph-\u00acng 1 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o \u00ab tr\u00e8ng : S\u00e8 m\u00c6t, c\u00b9nh, \u00ae\u00d8nh S\u00e8 m\u00c6t S\u00e8 c\u00b9nh S\u00e8 \u00ae\u00d8nh H\u00d7nh H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt H\u00d7nh l\u00cbp ph\u00f0\u00acng 2 a) H\u00b7y ch\u00d8 ra nh\u00f7ng c\u00b9nh b\u00bbng nhau c\u00f1a h\u00d7nh h\u00e9p A B ch\u00f7 nh\u00cbt (h\u00d7nh b\u00aan). D C b) Bi\u00d5t h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 6cm, chi\u00d2u M N r\u00e9ng 3cm, chi\u00d2u cao 4cm. T\u00ddnh di\u00d6n t\u00ddch c\u00f1a m\u00c6t \u00ae\u00b8y MNPQ v\u00b5 c\u00b8c m\u00c6t b\u00aan ABNM, BCPN. Q P 3 Trong c\u00b8c h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y h\u00d7nh n\u00b5o l\u00b5 h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt, h\u00d7nh n\u00b5o l\u00b5 h\u00d7nh l\u00cbp ph\u00f0\u00acng ? 8cm 12cm 11cm 8cm 4cm 5cm 8cm 10cm 6cm 8cm 6cm 108","5cm Di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt a) Di\u00d6n t\u00ddch xung quanh Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt l\u00b5 t\u00e6ng di\u00d6n t\u00ddch b\u00e8n m\u00c6t b\u00aan c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt. V\u00dd d\u00f4 : Cho h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 8cm, chi\u00d2u r\u00e9ng 5cm v\u00b5 chi\u00d2u cao 4cm. T\u00ddnh di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt \u00ae\u00e3. 4cm 5cm 8cm 5cm 8cm 4cm 8cm Quan s\u00b8t h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt v\u00b5 h\u00d7nh khai tri\u00d3n tr\u00aan \u00ae\u00a9y ta th\u00cay : Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt b\u00bbng di\u00d6n t\u00ddch c\u00f1a h\u00d7nh ch\u00f7 nh\u00cbt c\u00e3 : Chi\u00d2u d\u00b5i l\u00b5 : 5 + 8 + 5 + 8 = 26 (cm) (t\u00f8c l\u00b5 b\u00bbng chu vi c\u00f1a m\u00c6t \u00ae\u00b8y h\u00d7nh h\u00e9p), chi\u00d2u r\u00e9ng 4cm (t\u00f8c l\u00b5 b\u00bbng chi\u00d2u cao h\u00d7nh h\u00e9p). Do \u00ae\u00e3, di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt \u00ae\u00e3 l\u00b5 : 26 \u00d7 4 = 104 (cm2) Mu\u00e8n t\u00ddnh di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt ta l\u00cay chu vi m\u00c6t \u00ae\u00b8y nh\u00a9n v\u00edi chi\u00d2u cao (c\u00efng m\u00e9t \u00ae\u00acn v\u00de \u00aeo). b) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt l\u00b5 t\u00e6ng c\u00f1a di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch hai \u00ae\u00b8y. H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt \u00eb v\u00dd d\u00f4 tr\u00aan c\u00e3 di\u00d6n t\u00ddch m\u00e9t m\u00c6t \u00ae\u00b8y l\u00b5 : 8 \u00d7 5 = 40 (cm2) Do \u00ae\u00e3, di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt \u00ae\u00e3 l\u00b5 : 104 + 40 \u00d7 2 = 184 (cm2) 109","1 T\u00ddnh di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 5dm, chi\u00d2u r\u00e9ng 4dm v\u00b5 chi\u00d2u cao 3dm. 2 M\u00e9t ng\u00f0\u00eai th\u00ee g\u00df m\u00e9t c\u00b8i th\u00efng t\u00abn kh\u00abng n\u00bep d\u00b9ng h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 6dm, chi\u00d2u r\u00e9ng 4dm v\u00b5 chi\u00d2u cao 9dm. T\u00ddnh di\u00d6n t\u00ddch t\u00abn d\u00efng \u00ae\u00d3 l\u00b5m th\u00efng (kh\u00abng t\u00ddnh m\u00d0p h\u00b5n). Luy\u00d6n t\u00cbp 1 T\u00ddnh di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 : a) Chi\u00d2u d\u00b5i 25dm, chi\u00d2u r\u00e9ng 1,5m v\u00b5 chi\u00d2u cao 18dm ; b) Chi\u00d2u d\u00b5i m, chi\u00d2u r\u00e9ng m v\u00b5 chi\u00d2u cao m. 2 M\u00e9t c\u00b8i th\u00efng kh\u00abng n\u00bep d\u00b9ng h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 1,5m, chi\u00d2u r\u00e9ng 0,6m v\u00b5 chi\u00d2u cao 8dm. Ng\u00f0\u00eai ta s\u00acn m\u00c6t ngo\u00b5i c\u00f1a th\u00efng. H\u00e1i di\u00d6n t\u00ddch qu\u00d0t s\u00acn l\u00b5 bao nhi\u00aau m\u00d0t vu\u00abng ? 3 \u00a7\u00f3ng ghi \u00a7, sai ghi S : 2,5dm 1,2dm 1,2dm 2,5dm 1,5dm 1,5dm a) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a hai h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt b\u00bbng nhau. b) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a hai h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt kh\u00abng b\u00bbng nhau. c) Di\u00d6n t\u00ddch xung quanh c\u00f1a hai h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt b\u00bbng nhau. d) Di\u00d6n t\u00ddch xung quanh c\u00f1a hai h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt kh\u00abng b\u00bbng nhau. 110","Di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng a) C\u00b8c m\u00c6t c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng l\u00b5 c\u00b8c h\u00d7nh vu\u00abng b\u00bbng nhau n\u00aan : Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng b\u00bbng di\u00d6n t\u00ddch m\u00e9t m\u00c6t nh\u00a9n v\u00edi 4. Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng b\u00bbng di\u00d6n t\u00ddch m\u00e9t m\u00c6t nh\u00a9n v\u00edi 6. b) V\u00dd d\u00f4 : T\u00ddnh di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 5cm. \u2212 Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh 5cm l\u00cbp ph\u00f0\u00acng \u00ae\u00e3 l\u00b5 : (5 \u00d7 5) \u00d7 4 = 100 (cm2) 5cm 5cm \u2212 Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng \u00ae\u00e3 l\u00b5 : (5 \u00d7 5) \u00d7 6 = 150 (cm2) 1 T\u00ddnh di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 1,5m. 2 Ng\u00f0\u00eai ta l\u00b5m m\u00e9t c\u00b8i h\u00e9p kh\u00abng c\u00e3 n\u00bep b\u00bbng b\u00d7a c\u00f8ng d\u00b9ng h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 2,5dm. T\u00ddnh di\u00d6n t\u00ddch b\u00d7a c\u00c7n d\u00efng \u00ae\u00d3 l\u00b5m h\u00e9p (kh\u00abng t\u00ddnh m\u00d0p d\u00b8n). 111","Luy\u00d6n t\u00cbp 1 T\u00ddnh di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 2m 5cm. 2 M\u00b6nh b\u00d7a n\u00b5o d\u00f0\u00edi \u00ae\u00a9y c\u00e3 th\u00d3 g\u00cap \u00ae\u00f0\u00eec m\u00e9t h\u00d7nh l\u00cbp ph\u00f0\u00acng ? 1cm 1cm 1cm 1cm 1cm 1cm 1cm H\u00d7nh 1 H\u00d7nh 2 1cm 1cm 1cm 1cm 1cm 1cm 1cm 1cm H\u00d7nh 4 H\u00d7nh 3 3 \u00a7\u00f3ng ghi \u00a7, sai ghi S : 5cm 10cm 112","a) Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng g\u00cap 2 l\u00c7n di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng b) Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng g\u00cap 4 l\u00c7n di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng c) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng g\u00cap 2 l\u00c7n di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng d) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng g\u00cap 4 l\u00c7n di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng Luy\u00d6n t\u00cbp chung 1 T\u00ddnh di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 : a) Chi\u00d2u d\u00b5i 2,5m, chi\u00d2u r\u00e9ng 1,1m v\u00b5 chi\u00d2u cao 0,5m. b) Chi\u00d2u d\u00b5i 3m, chi\u00d2u r\u00e9ng 15dm v\u00b5 chi\u00d2u cao 9dm. 2 Vi\u00d5t s\u00e8 \u00aeo th\u00ddch h\u00eep v\u00b5o \u00ab tr\u00e8ng : H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt (1) (2) (3) Chi\u00d2u d\u00b5i 4m cm 0,4dm Chi\u00d2u r\u00e9ng 3m 0,4dm Chi\u00d2u cao 5m cm 0,4dm Chu vi m\u00c6t \u00ae\u00b8y 2cm Di\u00d6n t\u00ddch xung quanh Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n Nh\u00cbn x\u00d0t : H\u00d7nh l\u00cbp ph\u00f0\u00acng l\u00b5 h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i, chi\u00d2u r\u00e9ng v\u00b5 chi\u00d2u cao b\u00bbng nhau. 113","3 M\u00e9t h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 4cm, n\u00d5u g\u00cap c\u00b9nh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng l\u00aan 3 l\u00c7n th\u00d7 di\u00d6n t\u00ddch xung quanh v\u00b5 di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a n\u00e3 g\u00cap l\u00aan bao nhi\u00aau l\u00c7n ? T\u00b9i sao ? Th\u00d3 t\u00ddch c\u00f1a m\u00e9t h\u00d7nh a) V\u00dd d\u00f4 1 Trong h\u00d7nh b\u00aan, h\u00d7nh l\u00cbp ph\u00f0\u00acng n\u00bbm ho\u00b5n to\u00b5n trong h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt. Ta n\u00e3i : Th\u00d3 t\u00ddch h\u00d7nh l\u00cbp ph\u00f0\u00acng b\u00d0 h\u00acn th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt hay th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt l\u00edn h\u00acn th\u00d3 t\u00ddch h\u00d7nh l\u00cbp ph\u00f0\u00acng. b) V\u00dd d\u00f4 2 H\u00d7nh g\u00e5m 4 h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00f0 nhau v\u00b5 h\u00d7nh c\u00f2ng g\u00e5m 4 h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00f0 th\u00d5. Ta n\u00e3i : Th\u00d3 t\u00ddch h\u00d7nh b\u00bbng th\u00d3 t\u00ddch h\u00d7nh . c) V\u00dd d\u00f4 3 H\u00d7nh g\u00e5m 6 h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00f0 nhau. Ta t\u00b8ch h\u00d7nh th\u00b5nh hai h\u00d7nh v\u00b5 : h\u00d7nh g\u00e5m 4 h\u00d7nh l\u00cbp ph\u00f0\u00acng v\u00b5 h\u00d7nh g\u00e5m 2 h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00f0 th\u00d5. Ta n\u00e3i : Th\u00d3 t\u00ddch h\u00d7nh b\u00bbng t\u00e6ng th\u00d3 t\u00ddch c\u00b8c h\u00d7nh v\u00b5 . 114","1 Trong hai h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y : 1cm 1cm H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt g\u00e5m m\u00cay h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 ? H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt g\u00e5m m\u00cay h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 ? H\u00d7nh n\u00b5o c\u00e3 th\u00d3 t\u00ddch l\u00edn h\u00acn ? 2 H\u00d7nh g\u00e5m m\u00cay h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 ? H\u00d7nh g\u00e5m m\u00cay h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 ? So s\u00b8nh th\u00d3 t\u00ddch c\u00f1a h\u00d7nh v\u00b5 h\u00d7nh . 3 C\u00e3 6 h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 c\u00b9nh 1cm. H\u00b7y x\u00d5p 6 h\u00d7nh l\u00cbp ph\u00f0\u00acng \u00ae\u00e3 th\u00b5nh m\u00e9t h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt. C\u00e3 bao nhi\u00aau c\u00b8ch x\u00d5p kh\u00b8c nhau ? 115","X\u00a8ng-ti-m\u00d0t kh\u00e8i. \u00a7\u00d2-xi-m\u00d0t kh\u00e8i \u00a7\u00d3 \u00aeo th\u00d3 t\u00ddch ng\u00f0\u00eai ta c\u00e3 th\u00d3 d\u00efng nh\u00f7ng \u00ae\u00acn v\u00de : x\u00a8ng-ti-m\u00d0t kh\u00e8i, \u00ae\u00d2-xi-m\u00d0t kh\u00e8i. a) X\u00a8ng-ti-m\u00d0t kh\u00e8i l\u00b5 th\u00d3 t\u00ddch c\u00f1a 1dm h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh d\u00b5i 1cm. 1dm X\u00a8ng-ti-m\u00d0t kh\u00e8i vi\u00d5t t\u00bet l\u00b5 cm3. 1dm 1dm3 b) \u00a7\u00d2-xi-m\u00d0t kh\u00e8i l\u00b5 th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh d\u00b5i 1dm. \u00a7\u00d2-xi-m\u00d0t kh\u00e8i vi\u00d5t t\u00bet l\u00b5 dm3. c) H\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00b9nh 1dm g\u00e5m : 10 \u00d7 10 \u00d7 10 = 1000 h\u00d7nh l\u00cbp ph\u00f0\u00acng 1cm3 c\u00b9nh 1cm. Ta c\u00e3 : 1dm3 = 1000cm3 1 Vi\u00d5t v\u00b5o \u00ab tr\u00e8ng (theo m\u00c9u) : Vi\u00d5t s\u00e8 \u00a7\u00e4c s\u00e8 76cm3 b\u00b6y m\u00f0\u00aci s\u00b8u x\u00a8ng-ti-m\u00d0t kh\u00e8i 519dm3 85,08dm3 cm3 m\u00e9t tr\u00a8m ch\u00ddn m\u00f0\u00aci hai x\u00a8ng-ti-m\u00d0t kh\u00e8i hai ngh\u00d7n kh\u00abng tr\u00a8m linh m\u00e9t \u00ae\u00d2-xi-m\u00d0t kh\u00e8i ba ph\u00c7n t\u00b8m x\u00a8ng-ti-m\u00d0t kh\u00e8i 116","2 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam : a) 1dm3 = ... cm3 375dm3 = ... cm3 5,8dm3 = ... cm3 dm3 = ... cm3 b) 2000cm3 = ... dm3 154 000cm3 = ... dm3 490 000cm3 = ... dm3 5100cm3 = ... dm3 M\u00d0t kh\u00e8i a) M\u00d0t kh\u00e8i 1m 1m3 \u00a7\u00d3 \u00aeo th\u00d3 t\u00ddch ng\u00f0\u00eai ta c\u00dfn d\u00efng \u00ae\u00acn 1m v\u00de m\u00d0t kh\u00e8i. 1dm3 G M\u00d0t kh\u00e8i l\u00b5 th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh d\u00b5i 1m. M\u00d0t kh\u00e8i vi\u00d5t t\u00bet l\u00b5 m3. 1m G H\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00b9nh 1m g\u00e5m 1000 h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00b9nh 1dm. Ta c\u00e3 : 1m3 = 1000dm3 1m3 = 1 000 000cm3 (= 100 \u00d7 100 \u00d7 100). b) Nh\u00cbn x\u00d0t G M\u00e7i \u00ae\u00acn v\u00de \u00aeo th\u00d3 t\u00ddch g\u00cap 1000 l\u00c7n \u00ae\u00acn v\u00de b\u00d0 h\u00acn ti\u00d5p li\u00d2n. G M\u00e7i \u00ae\u00acn v\u00de \u00aeo th\u00d3 t\u00ddch b\u00bbng 1 \u00ae\u00acn v\u00de l\u00edn h\u00acn ti\u00d5p li\u00d2n. 1000 m3 dm3 cm3 1m3 1dm3 1cm3 = 1000dm3 = 1000cm3 = 1 dm3 1000 1 m3 = 1000 117","1 a) \u00a7\u00e4c c\u00b8c s\u00e8 \u00aeo : m3 ; 0,911m3. 15m3 ; 205m3 ; b) Vi\u00d5t c\u00b8c s\u00e8 \u00aeo th\u00d3 t\u00ddch : B\u00b6y ngh\u00d7n hai tr\u00a8m m\u00d0t kh\u00e8i ; B\u00e8n tr\u00a8m m\u00d0t kh\u00e8i ; M\u00e9t ph\u00c7n t\u00b8m m\u00d0t kh\u00e8i ; Kh\u00abng ph\u00c8y kh\u00abng n\u00a8m m\u00d0t kh\u00e8i. 2 a) Vi\u00d5t c\u00b8c s\u00e8 \u00aeo sau d\u00f0\u00edi d\u00b9ng s\u00e8 \u00aeo c\u00e3 \u00ae\u00acn v\u00de l\u00b5 \u00ae\u00d2-xi-m\u00d0t kh\u00e8i : 1cm3 ; 5,216m3 ; 13,8m3 ; 0,22m3. b) Vi\u00d5t c\u00b8c s\u00e8 \u00aeo sau d\u00f0\u00edi d\u00b9ng s\u00e8 \u00aeo c\u00e3 \u00ae\u00acn v\u00de l\u00b5 x\u00a8ng-ti-m\u00d0t kh\u00e8i : 1dm3 ; 1,969dm3 ; m3 ; 19,54m3. 3 Ng\u00f0\u00eai ta l\u00b5m m\u00e9t c\u00b8i h\u00e9p d\u00b9ng h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt b\u00bbng b\u00d7a. Bi\u00d5t r\u00bbng h\u00e9p \u00ae\u00e3 c\u00e3 chi\u00d2u d\u00b5i 5dm, chi\u00d2u r\u00e9ng 3dm v\u00b5 chi\u00d2u cao 2dm. H\u00e1i c\u00e3 th\u00d3 x\u00d5p \u00ae\u00f0\u00eec bao nhi\u00aau h\u00d7nh l\u00cbp ph\u00f0\u00acng 1dm3 \u00ae\u00d3 \u00ae\u00c7y c\u00b8i h\u00e9p \u00ae\u00e3 ? 2dm 3dm 5dm 118","Luy\u00d6n t\u00cbp m3 1 a) \u00a7\u00e4c c\u00b8c s\u00e8 \u00aeo : 5m3 ; 2010cm3 ; 2005dm3 ; 10,125m3 ; 0,109cm3 ; 0,015dm3 ; ; dm3. b) Vi\u00d5t c\u00b8c s\u00e8 \u00aeo th\u00d3 t\u00ddch : M\u00e9t ngh\u00d7n ch\u00ddn tr\u00a8m n\u00a8m m\u00f0\u00aci hai x\u00a8ng-ti-m\u00d0t kh\u00e8i ; Hai ngh\u00d7n kh\u00abng tr\u00a8m m\u00f0\u00eai l\u00a8m m\u00d0t kh\u00e8i ; Ba ph\u00c7n t\u00b8m \u00ae\u00d2-xi-m\u00d0t kh\u00e8i ; Kh\u00abng ph\u00c8y ch\u00ddn tr\u00a8m m\u00f0\u00eai ch\u00ddn m\u00d0t kh\u00e8i. 2 \u00a7\u00f3ng ghi \u00a7, sai ghi S : 0,25m3 l\u00b5 : a) Kh\u00abng ph\u00c8y hai m\u00f0\u00aci l\u00a8m m\u00d0t kh\u00e8i. b) Kh\u00abng ph\u00c8y hai tr\u00a8m n\u00a8m m\u00f0\u00aci m\u00d0t kh\u00e8i. c) Hai m\u00f0\u00aci l\u00a8m ph\u00c7n tr\u00a8m m\u00d0t kh\u00e8i. d) Hai m\u00f0\u00aci l\u00a8m ph\u00c7n ngh\u00d7n m\u00d0t kh\u00e8i. 3 So s\u00b8nh c\u00b8c s\u00e8 \u00aeo sau \u00ae\u00a9y : a) 913,232413m3 v\u00b5 913 232 413cm3. b) m3 v\u00b5 12,345m3. c) m3 v\u00b5 8 372 361dm3. 119","Th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt a) V\u00dd d\u00f4 : T\u00ddnh th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 20cm, chi\u00d2u r\u00e9ng 16cm v\u00b5 chi\u00d2u cao 10cm. \u00a7\u00d3 t\u00ddnh th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt tr\u00aan \u00ae\u00a9y b\u00bbng x\u00a8ng-ti-m\u00d0t kh\u00e8i ta c\u00c7n t\u00d7m s\u00e8 h\u00d7nh l\u00cbp ph\u00f0\u00acng 1cm3 x\u00d5p v\u00b5o \u00ae\u00c7y h\u00e9p (xem c\u00b8c h\u00d7nh v\u00cf d\u00f0\u00edi \u00ae\u00a9y). Sau khi x\u00d5p 10 l\u00edp h\u00d7nh l\u00cbp ph\u00f0\u00acng 1cm3 th\u00d7 v\u00f5a \u00ae\u00c7y h\u00e9p. M\u00e7i l\u00edp c\u00e3 : 20 \u00d7 16 = 320 (h\u00d7nh l\u00cbp ph\u00f0\u00acng 1cm3). 10 l\u00edp c\u00e3 : 320 \u00d7 10 = 3200 (h\u00d7nh l\u00cbp ph\u00f0\u00acng 1cm3). V\u00cby th\u00d3 t\u00ddch c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt l\u00b5 : 20 \u00d7 16 \u00d7 10 = 3200 (cm3) 10cm 16cm 20cm 120","b) Mu\u00e8n t\u00ddnh th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt ta l\u00cay chi\u00d2u d\u00b5i nh\u00a9n v\u00edi chi\u00d2u r\u00e9ng r\u00e5i nh\u00a9n v\u00edi chi\u00d2u cao (c\u00efng m\u00e9t \u00ae\u00acn v\u00de \u00aeo). G\u00e4i V l\u00b5 th\u00d3 t\u00ddch c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt, c ta c\u00e3 : V=a\u00d7b\u00d7c (a, b, c l\u00b5 ba k\u00ddch th\u00f0\u00edc c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt) b a 1 T\u00ddnh th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i a, chi\u00d2u r\u00e9ng b, chi\u00d2u cao c : a) a = 5cm ; b = 4cm ; c = 9cm. b) a = 1,5m ; b = 1,1m ; c = 0,5m. c) a = dm ; b = dm ; c = dm. 2 T\u00ddnh th\u00d3 t\u00ddch c\u00f1a kh\u00e8i g\u00e7 c\u00e3 d\u00b9ng nh\u00f0 h\u00d7nh b\u00aan. 12cm 15cm 5cm 6cm 3 T\u00ddnh th\u00d3 t\u00ddch c\u00f1a h\u00dfn \u00ae\u00b8 n\u00bbm trong b\u00d3 8cm n\u00f0\u00edc theo h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y : 7cm 10cm 5cm 10cm 10cm 10cm 121","Th\u00d3 t\u00ddch h\u00d7nh l\u00cbp ph\u00f0\u00acng 3cm a) V\u00dd d\u00f4 3cm N\u00d5u h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 3cm c\u00b9nh 3cm th\u00d7 th\u00d3 t\u00ddch l\u00b5 : V = 3 \u00d7 3 \u00d7 3 = 27 (cm3) a a 1cm3 a b) Mu\u00e8n t\u00ddnh th\u00d3 t\u00ddch h\u00d7nh l\u00cbp ph\u00f0\u00acng ta l\u00cay c\u00b9nh nh\u00a9n v\u00edi c\u00b9nh r\u00e5i nh\u00a9n v\u00edi c\u00b9nh. H\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh a th\u00d7 th\u00d3 t\u00ddch V l\u00b5 : V=a\u00d7a\u00d7a 1 Vi\u00d5t s\u00e8 \u00aeo th\u00ddch h\u00eep v\u00b5o \u00ab tr\u00e8ng : H\u00d7nh l\u00cbp ph\u00f0\u00acng (1) (2) (3) (4) \u00a7\u00e9 d\u00b5i c\u00b9nh 1,5m dm Di\u00d6n t\u00ddch m\u00e9t m\u00c6t 36cm2 Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n Th\u00d3 t\u00ddch 600dm2 2 M\u00e9t kh\u00e8i kim lo\u00b9i h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh l\u00b5 0,75m. M\u00e7i \u00ae\u00d2-xi-m\u00d0t kh\u00e8i kim lo\u00b9i \u00ae\u00e3 c\u00a9n n\u00c6ng 15kg. H\u00e1i kh\u00e8i kim lo\u00b9i \u00ae\u00e3 c\u00a9n n\u00c6ng bao nhi\u00aau ki-l\u00ab-gam ? 122","3 M\u00e9t h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 8cm, chi\u00d2u r\u00e9ng 7cm v\u00b5 chi\u00d2u cao 9cm. M\u00e9t h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh b\u00bbng trung b\u00d7nh c\u00e9ng c\u00f1a ba k\u00ddch th\u00f0\u00edc c\u00f1a h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt tr\u00aan. T\u00ddnh : a) Th\u00d3 t\u00ddch h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt ; b) Th\u00d3 t\u00ddch h\u00d7nh l\u00cbp ph\u00f0\u00acng. Luy\u00d6n t\u00cbp chung 1 M\u00e9t h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 2,5cm. T\u00ddnh di\u00d6n t\u00ddch m\u00e9t m\u00c6t, di\u00d6n t\u00ddch to\u00b5n ph\u00c7n v\u00b5 th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng \u00ae\u00e3. 2 Vi\u00d5t s\u00e8 \u00aeo th\u00ddch h\u00eep v\u00b5o \u00ab tr\u00e8ng : H\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt (1) (2) (3) Chi\u00d2u d\u00b5i 11cm 0,4m dm Chi\u00d2u r\u00e9ng 10cm 0,25m dm Chi\u00d2u cao 6cm 0,9m dm Di\u00d6n t\u00ddch m\u00c6t \u00ae\u00b8y Di\u00d6n t\u00ddch xung quanh Th\u00d3 t\u00ddch 3 M\u00e9t kh\u00e8i g\u00e7 d\u00b9ng h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 4cm 5cm c\u00b8c k\u00ddch th\u00f0\u00edc nh\u00f0 h\u00d7nh b\u00aan, ng\u00f0\u00eai ta c\u00bet 9cm 6cm \u00aei m\u00e9t ph\u00c7n kh\u00e8i g\u00e7 c\u00e3 d\u00b9ng h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00b9nh 4cm. T\u00ddnh th\u00d3 t\u00ddch ph\u00c7n 123 g\u00e7 c\u00dfn l\u00b9i.","Luy\u00d6n t\u00cbp chung 1 B\u00b9n Dung t\u00ddnh nh\u00c8m 15% c\u00f1a 120 nh\u00f0 sau : 10% c\u00f1a 120 l\u00b5 12 5% c\u00f1a 120 l\u00b5 6 V\u00cby : 15% c\u00f1a 120 l\u00b5 18. a) H\u00b7y vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam \u00ae\u00d3 t\u00d7m 17,5% c\u00f1a 240 theo c\u00b8ch t\u00ddnh c\u00f1a b\u00b9n Dung : ... % c\u00f1a 240 l\u00b5 ... ... % c\u00f1a 240 l\u00b5 ... ... % c\u00f1a 240 l\u00b5 ... V\u00cby : 17,5% c\u00f1a 240 l\u00b5 ... b) H\u00b7y t\u00ddnh 35% c\u00f1a 520 v\u00b5 n\u00aau c\u00b8ch t\u00ddnh. 2 Bi\u00d5t t\u00d8 s\u00e8 th\u00d3 t\u00ddch c\u00f1a hai h\u00d7nh l\u00cbp ph\u00f0\u00acng l\u00b5 2 : 3 (xem h\u00d7nh v\u00cf). Th\u00d3 t\u00ddch : 64cm3 Th\u00d3 t\u00ddch : ...cm3 ? a) Th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng l\u00edn b\u00bbng bao nhi\u00aau ph\u00c7n tr\u00a8m th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng b\u00d0 ? b) T\u00ddnh th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng l\u00edn. 124","3 B\u00b9n H\u00b9nh x\u00d5p c\u00b8c h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 2 2 c\u00e3 c\u00b9nh 1cm th\u00b5nh h\u00d7nh b\u00aan. H\u00e1i : 4 a) H\u00d7nh b\u00aan c\u00e3 bao nhi\u00aau h\u00d7nh l\u00cbp ph\u00f0\u00acng nh\u00e1 ? b) N\u00d5u s\u00acn c\u00b8c m\u00c6t ngo\u00b5i c\u00f1a h\u00d7nh b\u00aan th\u00d7 di\u00d6n t\u00ddch c\u00c7n s\u00acn b\u00bbng bao nhi\u00aau x\u00a8ng-ti-m\u00d0t vu\u00abng ? 4 Gi\u00edi thi\u00d6u h\u00d7nh tr\u00f4. gi\u00edi thi\u00d6u h\u00d7nh c\u00c7u a) Gi\u00edi thi\u00d6u h\u00d7nh tr\u00f4 C\u00d6NG TY S\u00db\u00c4A VI\u00cf\u00c5T NAM KH\u00d6\u00cbI L\u00db\u00da\u00c5NG T\u00d5NH 395g H\u00e9p s\u00f7a c\u00e3 d\u00b9ng h\u00d7nh tr\u00f4 H\u00d7nh tr\u00f4 H\u00d7nh tr\u00f4 c\u00e3 hai m\u00c6t \u00ae\u00b8y l\u00b5 hai h\u00d7nh tr\u00dfn b\u00bbng nhau v\u00b5 m\u00e9t m\u00c6t xung quanh. b) Gi\u00edi thi\u00d6u h\u00d7nh c\u00c7u Qu\u00b6 b\u00e3ng \u00ae\u00b8 c\u00e3 d\u00b9ng h\u00d7nh c\u00c7u Tr\u00b8i \u00a7\u00cat c\u00e3 d\u00b9ng h\u00d7nh c\u00c7u H\u00d7nh c\u00c7u 125","1 Trong c\u00b8c h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y c\u00e3 h\u00d7nh n\u00b5o l\u00b5 h\u00d7nh tr\u00f4 ? 2 \u00a7\u00e5 v\u00cbt n\u00b5o d\u00f0\u00edi \u00ae\u00a9y c\u00e3 d\u00b9ng h\u00d7nh c\u00c7u ? Qu\u00b6 b\u00e3ng b\u00b5n C\u00d6NG TY CHE\u00c2 VI\u00cf\u00c5T NAM Vi\u00aan bi H\u00e9p ch\u00cc Qu\u00b6 tr\u00f8ng g\u00b5 B\u00b8nh xe \u00ae\u00b9p 3 H\u00b7y k\u00d3 t\u00aan m\u00e9t v\u00b5i \u00ae\u00e5 v\u00cbt c\u00e3 d\u00b9ng : a) H\u00d7nh tr\u00f4 ; b) H\u00d7nh c\u00c7u. 126","Luy\u00d6n t\u00cbp chung 1 Cho h\u00d7nh thang vu\u00abng ABCD (xem h\u00d7nh v\u00cf) c\u00e3 AB = 4cm, DC = 5cm, AD = 3cm. N\u00e8i D v\u00edi B \u00ae\u00f0\u00eec hai h\u00d7nh tam gi\u00b8c ABD v\u00b5 BDC. AB DC a) T\u00ddnh di\u00d6n t\u00ddch m\u00e7i h\u00d7nh tam gi\u00b8c \u00ae\u00e3. b) T\u00ddnh t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c ABD v\u00b5 di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c BDC. 2 Cho h\u00d7nh b\u00d7nh h\u00b5nh MNPQ (xem h\u00d7nh v\u00cf) c\u00e3 MN = 12cm, chi\u00d2u cao KH = 6cm. So s\u00b8nh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c KQP v\u00edi t\u00e6ng di\u00d6n t\u00ddch c\u00f1a h\u00d7nh tam gi\u00b8c MKQ v\u00b5 h\u00d7nh tam gi\u00b8c KNP. MK N Q HP B3cm 3 Tr\u00aan h\u00d7nh b\u00aan, h\u00b7y t\u00ddnh di\u00d6n t\u00ddch 4cm C ph\u00c7n \u00ae\u00b7 t\u00ab m\u00b5u c\u00f1a h\u00d7nh tr\u00dfn. 5cm A O 127","Luy\u00d6n t\u00cbp chung 1 M\u00e9t b\u00d3 k\u00ddnh nu\u00abi c\u00b8 d\u00b9ng h\u00d7nh h\u00e9p ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 1m, chi\u00d2u r\u00e9ng 50cm, chi\u00d2u cao 60cm. a) T\u00ddnh di\u00d6n t\u00ddch k\u00ddnh d\u00efng l\u00b5m b\u00d3 c\u00b8 \u00ae\u00e3 (b\u00d3 kh\u00abng c\u00e3 n\u00bep). b) T\u00ddnh th\u00d3 t\u00ddch b\u00d3 c\u00b8 \u00ae\u00e3. c) M\u00f8c n\u00f0\u00edc trong b\u00d3 cao b\u00bbng chi\u00d2u cao c\u00f1a b\u00d3. T\u00ddnh th\u00d3 t\u00ddch n\u00f0\u00edc trong b\u00d3 \u00ae\u00e3 (\u00ae\u00e9 d\u00b5y k\u00ddnh kh\u00abng \u00ae\u00b8ng k\u00d3). 2 M\u00e9t h\u00d7nh l\u00cbp ph\u00f0\u00acng c\u00e3 c\u00b9nh 1,5m. T\u00ddnh : a) Di\u00d6n t\u00ddch xung quanh c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng ; b) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng ; c) Th\u00d3 t\u00ddch c\u00f1a h\u00d7nh l\u00cbp ph\u00f0\u00acng. 3 C\u00e3 hai h\u00d7nh l\u00cbp ph\u00f0\u00acng. H\u00d7nh c\u00e3 c\u00b9nh d\u00b5i g\u00cap 3 l\u00c7n c\u00b9nh h\u00d7nh . a) Di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh g\u00cap m\u00cay l\u00c7n di\u00d6n t\u00ddch to\u00b5n ph\u00c7n c\u00f1a h\u00d7nh ? b) Th\u00d3 t\u00ddch c\u00f1a h\u00d7nh g\u00cap m\u00cay l\u00c7n th\u00d3 t\u00ddch c\u00f1a h\u00d7nh ? 128","Ch\u00f0\u00acng b\u00e8n S\u00e8 \u00aeo th\u00eai gian - to\u00b8n chuy\u00d3n \u00ae\u00e9ng \u00ae\u00d2u I - S\u00e8 \u00aeo th\u00eai gian Tr.129 B\u00b6ng \u00ae\u00acn v\u00de \u00aeo th\u00eai gian CM YK a) C\u00b8c \u00ae\u00acn v\u00de \u00aeo th\u00eai gian 1 tu\u00c7n l\u00d4 = 7 ng\u00b5y 1 th\u00d5 k\u00d8 = 100 n\u00a8m 1 ng\u00b5y = 24 gi\u00ea 1 n\u00a8m = 12 th\u00b8ng 1 gi\u00ea = 60 ph\u00f3t 1 n\u00a8m = 365 ng\u00b5y 1 ph\u00f3t = 60 gi\u00a9y 1 n\u00a8m nhu\u00cbn = 366 ng\u00b5y C\u00f8 4 n\u00a8m l\u00b9i c\u00e3 1 n\u00a8m nhu\u00cbn Th\u00b8ng m\u00e9t, th\u00b8ng ba, th\u00b8ng n\u00a8m, th\u00b8ng b\u00b6y, th\u00b8ng t\u00b8m, th\u00b8ng m\u00f0\u00eai, th\u00b8ng m\u00f0\u00eai hai c\u00e3 31 ng\u00b5y. Th\u00b8ng t\u00f0, th\u00b8ng s\u00b8u, th\u00b8ng ch\u00ddn, th\u00b8ng m\u00f0\u00eai m\u00e9t c\u00e3 30 ng\u00b5y. Th\u00b8ng hai c\u00e3 28 ng\u00b5y (v\u00b5o n\u00a8m nhu\u00cbn c\u00e3 29 ng\u00b5y). b) V\u00dd d\u00f4 v\u00d2 \u00ae\u00e6i \u00ae\u00acn v\u00de \u00aeo th\u00eai gian G M\u00e9t n\u00a8m r\u00f0\u00eci = 1,5 n\u00a8m = 12 th\u00b8ng \u00d7 1,5 = 18 th\u00b8ng. G gi\u00ea = 60 ph\u00f3t \u00d7 = 40 ph\u00f3t. G 0,5 gi\u00ea = 60 ph\u00f3t \u00d7 0,5 = 30 ph\u00f3t. 60 G 216 ph\u00f3t = 3 gi\u00ea 36 ph\u00f3t = 3,6 gi\u00ea : 3,6 216 60 36 3 216 ph\u00f3t = 3 gi\u00ea 36 ph\u00f3t 216 ph\u00f3t = 3,6 gi\u00ea 129","1 Trong l\u00dech s\u00f6 ph\u00b8t tri\u00d3n c\u00f1a lo\u00b5i ng\u00f0\u00eai \u00ae\u00b7 c\u00e3 nh\u00f7ng ph\u00b8t minh v\u00dc \u00ae\u00b9i. B\u00b6ng d\u00f0\u00edi \u00ae\u00a9y cho bi\u00d5t t\u00aan v\u00b5 n\u00a8m c\u00abng b\u00e8 m\u00e9t s\u00e8 ph\u00b8t minh. H\u00b7y \u00ae\u00e4c b\u00b6ng v\u00b5 cho bi\u00d5t t\u00f5ng ph\u00b8t minh \u00ae\u00f0\u00eec c\u00abng b\u00e8 v\u00b5o th\u00d5 k\u00d8 n\u00b5o. 130","2 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam : b) 3 gi\u00ea = ... ph\u00f3t a) 6 n\u00a8m = ... th\u00b8ng 1,5 gi\u00ea = ... ph\u00f3t 4 n\u00a8m 2 th\u00b8ng = ... th\u00b8ng gi\u00ea = ... ph\u00f3t 3 n\u00a8m r\u00f0\u00eci = ... th\u00b8ng 6 ph\u00f3t = ... gi\u00a9y 3 ng\u00b5y = ... gi\u00ea ph\u00f3t = ... gi\u00a9y 1 gi\u00ea = ... gi\u00a9y 0,5 ng\u00b5y = ... gi\u00ea 3 ng\u00b5y r\u00f0\u00eci = ... gi\u00ea 3 Vi\u00d5t s\u00e8 th\u00cbp ph\u00a9n th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam : a) 72 ph\u00f3t = ... gi\u00ea b) 30 gi\u00a9y = ... ph\u00f3t 270 ph\u00f3t = ... gi\u00ea 135 gi\u00a9y = ... ph\u00f3t C\u00e9ng s\u00e8 \u00aeo th\u00eai gian a) V\u00dd d\u00f4 1 : M\u00e9t \u00ab t\u00ab \u00aei t\u00f5 H\u00b5 N\u00e9i \u00ae\u00d5n Thanh Ho\u00b8 h\u00d5t 3 gi\u00ea 15 ph\u00f3t r\u00e5i \u00aei ti\u00d5p \u00ae\u00d5n Vinh h\u00d5t 2 gi\u00ea 35 ph\u00f3t. H\u00e1i \u00ab t\u00ab \u00ae\u00e3 \u00aei c\u00b6 qu\u00b7ng \u00ae\u00f0\u00eang t\u00f5 H\u00b5 N\u00e9i \u00ae\u00d5n Vinh h\u00d5t bao nhi\u00aau th\u00eai gian ? H\u00b5 N\u00e9i Thanh Ho\u00b8 Vinh Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p c\u00e9ng : 3 gi\u00ea 15 ph\u00f3t + 2 gi\u00ea 35 ph\u00f3t = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 3 gi\u00ea 15 ph\u00f3t + 2 gi\u00ea 35 ph\u00f3t 5 gi\u00ea 50 ph\u00f3t V\u00cby : 3 gi\u00ea 15 ph\u00f3t + 2 gi\u00ea 35 ph\u00f3t = 5 gi\u00ea 50 ph\u00f3t. 131","b) V\u00dd d\u00f4 2 : M\u00e9t ng\u00f0\u00eai tham gia \u00aeua xe \u00ae\u00b9p, qu\u00b7ng \u00ae\u00f0\u00eang \u00ae\u00c7u ti\u00aan \u00aei h\u00d5t 22 ph\u00f3t 58 gi\u00a9y, qu\u00b7ng \u00ae\u00f0\u00eang th\u00f8 hai \u00aei h\u00d5t 23 ph\u00f3t 25 gi\u00a9y. H\u00e1i ng\u00f0\u00eai \u00ae\u00e3 \u00aei c\u00b6 hai qu\u00b7ng \u00ae\u00f0\u00eang h\u00d5t bao nhi\u00aau th\u00eai gian ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p c\u00e9ng : 22 ph\u00f3t 58 gi\u00a9y + 23 ph\u00f3t 25 gi\u00a9y = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 22 ph\u00f3t 58 gi\u00a9y + 23 ph\u00f3t 25 gi\u00a9y 45 ph\u00f3t 83 gi\u00a9y (83 gi\u00a9y = 1 ph\u00f3t 23 gi\u00a9y) V\u00cby : 22 ph\u00f3t 58 gi\u00a9y + 23 ph\u00f3t 25 gi\u00a9y = 46 ph\u00f3t 23 gi\u00a9y. 1 T\u00ddnh : b) 3 ng\u00b5y 20 gi\u00ea + 4 ng\u00b5y 15 gi\u00ea a) 7 n\u00a8m 9 th\u00b8ng + 5 n\u00a8m 6 th\u00b8ng 4 ph\u00f3t 13 gi\u00a9y + 5 ph\u00f3t 15 gi\u00a9y 3 gi\u00ea 5 ph\u00f3t + 6 gi\u00ea 32 ph\u00f3t 12 gi\u00ea 18 ph\u00f3t + 8 gi\u00ea 12 ph\u00f3t 8 ph\u00f3t 45 gi\u00a9y + 6 ph\u00f3t 15 gi\u00a9y 4 gi\u00ea 35 ph\u00f3t + 8 gi\u00ea 42 ph\u00f3t 12 ph\u00f3t 43 gi\u00a9y + 5 ph\u00f3t 37 gi\u00a9y 2 L\u00a9m \u00aei t\u00f5 nh\u00b5 \u00ae\u00d5n b\u00d5n xe h\u00d5t 35 ph\u00f3t, sau \u00ae\u00e3 \u00aei \u00ab t\u00ab \u00ae\u00d5n Vi\u00d6n B\u00b6o t\u00b5ng L\u00dech s\u00f6 h\u00d5t 2 gi\u00ea 20 ph\u00f3t. H\u00e1i L\u00a9m \u00aei t\u00f5 nh\u00b5 \u00ae\u00d5n Vi\u00d6n B\u00b6o t\u00b5ng L\u00dech s\u00f6 h\u00d5t bao nhi\u00aau th\u00eai gian ? Tr\u00f5 s\u00e8 \u00aeo th\u00eai gian a) V\u00dd d\u00f4 1 : M\u00e9t \u00ab t\u00ab \u00aei t\u00f5 Hu\u00d5 l\u00f3c 13 gi\u00ea 10 ph\u00f3t v\u00b5 \u00ae\u00d5n \u00a7\u00b5 N\u00bdng l\u00f3c 15 gi\u00ea 55 ph\u00f3t. H\u00e1i \u00ab t\u00ab \u00ae\u00e3 \u00aei t\u00f5 Hu\u00d5 \u00ae\u00d5n \u00a7\u00b5 N\u00bdng h\u00d5t bao nhi\u00aau th\u00eai gian ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p tr\u00f5 : 15 gi\u00ea 55 ph\u00f3t \u2212 13 gi\u00ea 10 ph\u00f3t = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 15 gi\u00ea 55 ph\u00f3t \u2212 13 gi\u00ea 10 ph\u00f3t 2 gi\u00ea 45 ph\u00f3t V\u00cby : 15 gi\u00ea 55 ph\u00f3t \u2212 13 gi\u00ea 10 ph\u00f3t = 2 gi\u00ea 45 ph\u00f3t. 132","b) V\u00dd d\u00f4 2 : Tr\u00aan c\u00efng m\u00e9t \u00aeo\u00b9n \u00ae\u00f0\u00eang, Ho\u00b5 ch\u00b9y h\u00d5t 3 ph\u00f3t 20 gi\u00a9y, B\u00d7nh ch\u00b9y h\u00d5t 2 ph\u00f3t 45 gi\u00a9y. H\u00e1i B\u00d7nh ch\u00b9y \u00ddt h\u00acn Ho\u00b5 bao nhi\u00aau gi\u00a9y ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p tr\u00f5 : 3 ph\u00f3t 20 gi\u00a9y \u2212 2 ph\u00f3t 45 gi\u00a9y = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 3 ph\u00f3t 20 gi\u00a9y 2 ph\u00f3t 80 gi\u00a9y \u2212 \u00ae\u00e6i th\u00b5nh \u2212 2 ph\u00f3t 45 gi\u00a9y 2 ph\u00f3t 45 gi\u00a9y 0 ph\u00f3t 35 gi\u00a9y V\u00cby : 3 ph\u00f3t 20 gi\u00a9y \u2212 2 ph\u00f3t 45 gi\u00a9y = 35 gi\u00a9y. 1 T\u00ddnh : a) 23 ph\u00f3t 25 gi\u00a9y \u2212 15 ph\u00f3t 12 gi\u00a9y ; b) 54 ph\u00f3t 21 gi\u00a9y \u2212 21 ph\u00f3t 34 gi\u00a9y ; c) 22 gi\u00ea 15 ph\u00f3t \u2212 12 gi\u00ea 35 ph\u00f3t. 2 T\u00ddnh : a) 23 ng\u00b5y 12 gi\u00ea \u2212 3 ng\u00b5y 8 gi\u00ea ; b) 14 ng\u00b5y 15 gi\u00ea \u2212 3 ng\u00b5y 17 gi\u00ea ; c) 13 n\u00a8m 2 th\u00b8ng \u2212 8 n\u00a8m 6 th\u00b8ng. 3 M\u00e9t ng\u00f0\u00eai \u00aei t\u00f5 A l\u00f3c 6 gi\u00ea 45 ph\u00f3t v\u00b5 \u00ae\u00d5n B l\u00f3c 8 gi\u00ea 30 ph\u00f3t. Gi\u00f7a \u00ae\u00f0\u00eang ng\u00f0\u00eai \u00ae\u00e3 ngh\u00d8 15 ph\u00f3t. H\u00e1i n\u00d5u kh\u00abng k\u00d3 th\u00eai gian ngh\u00d8, ng\u00f0\u00eai \u00ae\u00e3 \u00aei qu\u00b7ng \u00ae\u00f0\u00eang AB h\u00d5t bao nhi\u00aau th\u00eai gian ? 133","Luy\u00d6n t\u00cbp b) 1,6 gi\u00ea = ... ph\u00f3t 2 gi\u00ea 15 ph\u00f3t = ... ph\u00f3t 1 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam : 2,5 ph\u00f3t = ... gi\u00a9y a) 12 ng\u00b5y = ... gi\u00ea 3,4 ng\u00b5y = ... gi\u00ea 4 ph\u00f3t 25 gi\u00a9y = ... gi\u00a9y 4 ng\u00b5y 12 gi\u00ea = ... gi\u00ea gi\u00ea = ... ph\u00f3t 2 T\u00ddnh : a) 2 n\u00a8m 5 th\u00b8ng + 13 n\u00a8m 6 th\u00b8ng ; b) 4 ng\u00b5y 21 gi\u00ea + 5 ng\u00b5y 15 gi\u00ea ; c) 13 gi\u00ea 34 ph\u00f3t + 6 gi\u00ea 35 ph\u00f3t. 3 T\u00ddnh : a) 4 n\u00a8m 3 th\u00b8ng \u2212 2 n\u00a8m 8 th\u00b8ng ; b) 15 ng\u00b5y 6 gi\u00ea \u2212 10 ng\u00b5y 12 gi\u00ea ; c) 13 gi\u00ea 23 ph\u00f3t \u2212 5 gi\u00ea 45 ph\u00f3t. 4 N\u00a8m 1492, nh\u00b5 th\u00b8m hi\u00d3m Cri-xt\u00ab-ph\u00ac C\u00ab-l\u00abm-b\u00ab ph\u00b8t hi\u00d6n ra ch\u00a9u M\u00dc. N\u00a8m 1961, I-u-ri Ga-ga-rin l\u00b5 ng\u00f0\u00eai \u00ae\u00c7u ti\u00aan bay v\u00b5o v\u00f2 tr\u00f4. H\u00e1i hai s\u00f9 ki\u00d6n tr\u00aan c\u00b8ch nhau bao nhi\u00aau n\u00a8m ? Cri-xt\u00ab-ph\u00ac C\u00ab-l\u00abm-b\u00ab I-u-ri Ga-ga-rin 134","Nh\u00a9n s\u00e8 \u00aeo th\u00eai gian v\u00edi m\u00e9t s\u00e8 a) V\u00dd d\u00f4 1 : Trung b\u00d7nh m\u00e9t ng\u00f0\u00eai th\u00ee l\u00b5m xong m\u00e9t s\u00b6n ph\u00c8m h\u00d5t 1 gi\u00ea 10 ph\u00f3t. H\u00e1i ng\u00f0\u00eai \u00ae\u00e3 l\u00b5m 3 s\u00b6n ph\u00c8m nh\u00f0 th\u00d5 h\u00d5t bao nhi\u00aau th\u00eai gian ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p nh\u00a9n : 1 gi\u00ea 10 ph\u00f3t \u00d7 3 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 1 gi\u00ea 10 ph\u00f3t \u00d7 3 3 gi\u00ea 30 ph\u00f3t V\u00cby : 1 gi\u00ea 10 ph\u00f3t \u00d7 3 = 3 gi\u00ea 30 ph\u00f3t. b) V\u00dd d\u00f4 2 : M\u00e7i bu\u00e6i s\u00b8ng H\u00b9nh h\u00e4c \u00eb tr\u00f0\u00eang trung b\u00d7nh 3 gi\u00ea 15 ph\u00f3t. M\u00e9t tu\u00c7n l\u00d4 H\u00b9nh h\u00e4c \u00eb tr\u00f0\u00eang 5 bu\u00e6i. H\u00e1i m\u00e7i tu\u00c7n l\u00d4 H\u00b9nh h\u00e4c \u00eb tr\u00f0\u00eang bao nhi\u00aau th\u00eai gian ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p nh\u00a9n : 3 gi\u00ea 15 ph\u00f3t \u00d7 5 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 3 gi\u00ea 15 ph\u00f3t \u00d7 5 15 gi\u00ea 75 ph\u00f3t (75 ph\u00f3t = 1 gi\u00ea 15 ph\u00f3t) V\u00cby : 3 gi\u00ea 15 ph\u00f3t \u00d7 5 = 16 gi\u00ea 15 ph\u00f3t. 1 T\u00ddnh : b) 4,1 gi\u00ea \u00d7 6 a) 3 gi\u00ea 12 ph\u00f3t \u00d7 3 3,4 ph\u00f3t \u00d7 4 4 gi\u00ea 23 ph\u00f3t \u00d7 4 9,5 gi\u00a9y \u00d7 3 12 ph\u00f3t 25 gi\u00a9y \u00d7 5 2 M\u00e9t chi\u00d5c \u00aeu quay quay m\u00e7i v\u00dfng h\u00d5t 1 ph\u00f3t 25 gi\u00a9y. B\u00d0 Lan ng\u00e5i tr\u00aan \u00aeu quay v\u00b5 quay 3 v\u00dfng. H\u00e1i b\u00d0 Lan ng\u00e5i tr\u00aan \u00aeu quay bao nhi\u00aau l\u00a9u ? 135","Chia s\u00e8 \u00aeo th\u00eai gian cho m\u00e9t s\u00e8 a) V\u00dd d\u00f4 1 : H\u00b6i thi \u00ae\u00cau 3 v\u00b8n c\u00ea h\u00d5t 42 ph\u00f3t 30 gi\u00a9y. H\u00e1i trung b\u00d7nh H\u00b6i thi \u00ae\u00cau m\u00e7i v\u00b8n c\u00ea h\u00d5t bao l\u00a9u ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p chia : 42 ph\u00f3t 30 gi\u00a9y : 3 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 42 ph\u00f3t 30 gi\u00a9y 3 12 14 ph\u00f3t 10 gi\u00a9y 0 30 gi\u00a9y 00 V\u00cby : 42 ph\u00f3t 30 gi\u00a9y : 3 = 14 ph\u00f3t 10 gi\u00a9y. b) V\u00dd d\u00f4 2 : M\u00e9t v\u00d6 tinh nh\u00a9n t\u00b9o quay xung quanh Tr\u00b8i \u00a7\u00cat 4 v\u00dfng h\u00d5t 7 gi\u00ea 40 ph\u00f3t. H\u00e1i v\u00d6 tinh \u00ae\u00e3 quay xung quanh Tr\u00b8i \u00a7\u00cat 1 v\u00dfng h\u00d5t bao l\u00a9u ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p chia : 7 gi\u00ea 40 ph\u00f3t : 4 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 sau : 4 7 gi\u00ea 40 ph\u00f3t 3 gi\u00ea = 180 ph\u00f3t 1 gi\u00ea 55 ph\u00f3t 220 ph\u00f3t 20 0 V\u00cby : 7 gi\u00ea 40 ph\u00f3t : 4 = 1 gi\u00ea 55 ph\u00f3t. 1 T\u00ddnh : b) 35 gi\u00ea 40 ph\u00f3t : 5 ; a) 24 ph\u00f3t 12 gi\u00a9y : 4 ; d) 18,6 ph\u00f3t : 6. c) 10 gi\u00ea 48 ph\u00f3t : 9 ; 2 M\u00e9t ng\u00f0\u00eai th\u00ee l\u00b5m vi\u00d6c t\u00f5 l\u00f3c 7 gi\u00ea 30 ph\u00f3t \u00ae\u00d5n 12 gi\u00ea v\u00b5 l\u00b5m \u00ae\u00f0\u00eec 3 d\u00f4ng c\u00f4. H\u00e1i trung b\u00d7nh ng\u00f0\u00eai \u00ae\u00e3 l\u00b5m 1 d\u00f4ng c\u00f4 h\u00d5t bao nhi\u00aau th\u00eai gian ? 136","Luy\u00d6n t\u00cbp 1 T\u00ddnh : b) 36 ph\u00f3t 12 gi\u00a9y : 3 ; a) 3 gi\u00ea 14 ph\u00f3t \u00d7 3 ; d) 14 gi\u00ea 28 ph\u00f3t : 7. c) 7 ph\u00f3t 26 gi\u00a9y \u00d7 2 ; 2 T\u00ddnh : a) (3 gi\u00ea 40 ph\u00f3t + 2 gi\u00ea 25 ph\u00f3t) \u00d7 3 ; b) 3 gi\u00ea 40 ph\u00f3t + 2 gi\u00ea 25 ph\u00f3t \u00d7 3 ; c) (5 ph\u00f3t 35 gi\u00a9y + 6 ph\u00f3t 21 gi\u00a9y) : 4 ; d) 12 ph\u00f3t 3 gi\u00a9y \u00d7 2 + 4 ph\u00f3t 12 gi\u00a9y : 4. 3 Trung b\u00d7nh m\u00e9t ng\u00f0\u00eai th\u00ee l\u00b5m xong 1 s\u00b6n ph\u00c8m h\u00d5t 1 gi\u00ea 8 ph\u00f3t. L\u00c7n th\u00f8 nh\u00cat ng\u00f0\u00eai \u00ae\u00e3 l\u00b5m \u00ae\u00f0\u00eec 7 s\u00b6n ph\u00c8m. L\u00c7n th\u00f8 hai ng\u00f0\u00eai \u00ae\u00e3 l\u00b5m \u00ae\u00f0\u00eec 8 s\u00b6n ph\u00c8m. H\u00e1i c\u00b6 hai l\u00c7n ng\u00f0\u00eai \u00ae\u00e3 ph\u00b6i l\u00b5m trong bao nhi\u00aau th\u00eai gian ? 4 > ? 4,5 gi\u00ea ... 4 gi\u00ea 5 ph\u00f3t < 8 gi\u00ea 16 ph\u00f3t \u2212 1 gi\u00ea 25 ph\u00f3t ... 2 gi\u00ea 17 ph\u00f3t \u00d7 3 = 26 gi\u00ea 25 ph\u00f3t : 5 ... 2 gi\u00ea 40 ph\u00f3t + 2 gi\u00ea 45 ph\u00f3t. Luy\u00d6n t\u00cbp chung 1 T\u00ddnh : a) 17 gi\u00ea 53 ph\u00f3t + 4 gi\u00ea 15 ph\u00f3t ; b) 45 ng\u00b5y 23 gi\u00ea \u2212 24 ng\u00b5y 17 gi\u00ea ; c) 6 gi\u00ea 15 ph\u00f3t \u00d7 6 ; d) 21 ph\u00f3t 15 gi\u00a9y : 5. 2 T\u00ddnh : a) (2 gi\u00ea 30 ph\u00f3t + 3 gi\u00ea 15 ph\u00f3t) \u00d7 3 ; 2 gi\u00ea 30 ph\u00f3t + 3 gi\u00ea 15 ph\u00f3t \u00d7 3 ; b) (5 gi\u00ea 20 ph\u00f3t + 7 gi\u00ea 40 ph\u00f3t) : 2 ; 5 gi\u00ea 20 ph\u00f3t + 7 gi\u00ea 40 ph\u00f3t : 2. 137","3 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : H\u00f0\u00acng v\u00b5 H\u00e5ng h\u00d1n g\u00c6p nhau l\u00f3c 10 gi\u00ea 40 ph\u00f3t s\u00b8ng. H\u00f0\u00acng \u00ae\u00d5n ch\u00e7 h\u00d1n l\u00f3c 10 gi\u00ea 20 ph\u00f3t c\u00dfn H\u00e5ng l\u00b9i \u00ae\u00d5n mu\u00e9n m\u00cat 15 ph\u00f3t. H\u00e1i H\u00f0\u00acng ph\u00b6i \u00ae\u00eei H\u00e5ng trong bao nhi\u00aau l\u00a9u ? A. 20 ph\u00f3t B. 35 ph\u00f3t C. 55 ph\u00f3t D. 1 gi\u00ea 20 ph\u00f3t 4 B\u00b9n Lan xem gi\u00ea t\u00b5u t\u00f5 ga H\u00b5 N\u00e9i \u00aei m\u00e9t s\u00e8 n\u00aci nh\u00f0 sau : Ga xu\u00cat ph\u00b8t Ga \u00ae\u00d5n Gi\u00ea kh\u00ebi h\u00b5nh Gi\u00ea t\u00edi H\u00b5 N\u00e9i H\u00b6i Ph\u00dfng 6 gi\u00ea 05 ph\u00f3t 8 gi\u00ea 10 ph\u00f3t H\u00b5 N\u00e9i L\u00b5o Cai 22 gi\u00ea 6 gi\u00ea H\u00b5 N\u00e9i Qu\u00b8n Tri\u00d2u 14 gi\u00ea 20 ph\u00f3t 17 gi\u00ea 25 ph\u00f3t H\u00b5 N\u00e9i \u00a7\u00e5ng \u00a7\u00a8ng 5 gi\u00ea 45 ph\u00f3t 11 gi\u00ea 30 ph\u00f3t T\u00ddnh th\u00eai gian t\u00b5u \u00aei t\u00f5 ga H\u00b5 N\u00e9i \u00ae\u00d5n c\u00b8c ga H\u00b6i Ph\u00dfng, Qu\u00b8n Tri\u00d2u, \u00a7\u00e5ng \u00a7\u00a8ng, L\u00b5o Cai. II - V\u00cbn t\u00e8c, qu\u00b7ng \u00ae\u00f0\u00eang, th\u00eai gian V\u00cbn t\u00e8c a) B\u00b5i to\u00b8n 1 : M\u00e9t \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang d\u00b5i 170km h\u00d5t 4 gi\u00ea. H\u00e1i trung b\u00d7nh m\u00e7i gi\u00ea \u00ab t\u00ab \u00ae\u00e3 \u00aei \u00ae\u00f0\u00eec bao nhi\u00aau ki-l\u00ab-m\u00d0t ? ? km 170km B\u00b5i gi\u00b6i Trung b\u00d7nh m\u00e7i gi\u00ea \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec l\u00b5 : 170 : 4 = 42,5 (km) \u00a7\u00b8p s\u00e8 : 42,5km. 138","Nh\u00cbn x\u00d0t : Trung b\u00d7nh m\u00e7i gi\u00ea \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec 42,5km. Ta n\u00e3i v\u00cbn t\u00e8c trung b\u00d7nh hay n\u00e3i v\u00ben t\u00bet v\u00cbn t\u00e8c c\u00f1a \u00ab t\u00ab l\u00b5 b\u00e8n m\u00f0\u00aci hai ph\u00c8y n\u00a8m ki-l\u00ab-m\u00d0t gi\u00ea, vi\u00d5t t\u00bet l\u00b5 42,5 km\/gi\u00ea. V\u00cby v\u00cbn t\u00e8c c\u00f1a \u00ab t\u00ab l\u00b5 : 170 : 4 = 42,5 (km\/gi\u00ea) Mu\u00e8n t\u00ddnh v\u00cbn t\u00e8c ta l\u00cay qu\u00b7ng \u00ae\u00f0\u00eang chia cho th\u00eai gian. G\u00e4i v\u00cbn t\u00e8c l\u00b5 v, qu\u00b7ng \u00ae\u00f0\u00eang l\u00b5 s, th\u00eai gian l\u00b5 t, ta c\u00e3 : v=s:t b) B\u00b5i to\u00b8n 2 : M\u00e9t ng\u00f0\u00eai ch\u00b9y \u00ae\u00f0\u00eec 60m trong 10 gi\u00a9y. T\u00ddnh v\u00cbn t\u00e8c ch\u00b9y c\u00f1a ng\u00f0\u00eai \u00ae\u00e3. B\u00b5i gi\u00b6i V\u00cbn t\u00e8c ch\u00b9y c\u00f1a ng\u00f0\u00eai \u00ae\u00e3 l\u00b5 : 60 : 10 = 6 (m\/gi\u00a9y) \u00a7\u00b8p s\u00e8 : 6 m\/gi\u00a9y. 1 M\u00e9t ng\u00f0\u00eai \u00aei xe m\u00b8y \u00aei trong 3 gi\u00ea \u00ae\u00f0\u00eec 105km. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a ng\u00f0\u00eai \u00aei xe m\u00b8y. 2 M\u00e9t m\u00b8y bay bay \u00ae\u00f0\u00eec 1800km trong 2,5 gi\u00ea. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a m\u00b8y bay. 3 M\u00e9t ng\u00f0\u00eai ch\u00b9y \u00ae\u00f0\u00eec 400m trong 1 ph\u00f3t 20 gi\u00a9y. T\u00ddnh v\u00cbn t\u00e8c ch\u00b9y c\u00f1a ng\u00f0\u00eai \u00ae\u00e3 v\u00edi \u00ae\u00acn v\u00de \u00aeo l\u00b5 m\/gi\u00a9y. Luy\u00d6n t\u00cbp 1 M\u00e9t con \u00ae\u00b5 \u00aei\u00d3u khi c\u00c7n c\u00e3 th\u00d3 ch\u00b9y \u00ae\u00f0\u00eec 5250m trong 5 ph\u00f3t. T\u00ddnh v\u00cbn t\u00e8c ch\u00b9y c\u00f1a \u00ae\u00b5 \u00aei\u00d3u. 139","2 Vi\u00d5t v\u00b5o \u00ab tr\u00e8ng (theo m\u00c9u) : 147km 210m 1014m 3 gi\u00ea 6 gi\u00a9y 13 ph\u00f3t s 130km t 4 gi\u00ea v 32,5 km\/gi\u00ea 3 Qu\u00b7ng \u00ae\u00f0\u00eang AB d\u00b5i 25km. Tr\u00aan \u00ae\u00f0\u00eang \u00aei t\u00f5 A \u00ae\u00d5n B, m\u00e9t ng\u00f0\u00eai \u00aei b\u00e9 5km r\u00e5i ti\u00d5p t\u00f4c \u00aei \u00ab t\u00ab trong n\u00f6a gi\u00ea th\u00d7 \u00ae\u00d5n B. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a \u00ab t\u00ab. 4 M\u00e9t ca n\u00ab \u00aei t\u00f5 6 gi\u00ea 30 ph\u00f3t \u00ae\u00d5n 7 gi\u00ea 45 ph\u00f3t \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang 30km. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a ca n\u00ab. Qu\u00b7ng \u00ae\u00f0\u00eang a) B\u00b5i to\u00b8n 1 : M\u00e9t \u00ab t\u00ab \u00aei trong 4 gi\u00ea v\u00edi v\u00cbn t\u00e8c 42,5 km\/gi\u00ea. T\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang \u00aei \u00ae\u00f0\u00eec c\u00f1a \u00ab t\u00ab. B\u00b5i gi\u00b6i Qu\u00b7ng \u00ae\u00f0\u00eang \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec trong 4 gi\u00ea l\u00b5 : 42,5 \u00d7 4 = 170 (km) \u00a7\u00b8p s\u00e8 : 170km. Nh\u00cbn x\u00d0t : \u00a7\u00d3 t\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec ta l\u00cay qu\u00b7ng \u00ae\u00f0\u00eang \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec trong 1 gi\u00ea hay v\u00cbn t\u00e8c c\u00f1a \u00ab t\u00ab nh\u00a9n v\u00edi th\u00eai gian \u00aei. Mu\u00e8n t\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang ta l\u00cay v\u00cbn t\u00e8c nh\u00a9n v\u00edi th\u00eai gian. Ta c\u00e3 : s = v \u00d7 t 140","b) B\u00b5i to\u00b8n 2 : M\u00e9t ng\u00f0\u00eai \u00aei xe \u00ae\u00b9p v\u00edi v\u00cbn t\u00e8c 12 km\/gi\u00ea trong 2 gi\u00ea 30 ph\u00f3t. T\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang ng\u00f0\u00eai \u00ae\u00e3 \u00ae\u00b7 \u00aei \u00ae\u00f0\u00eec. B\u00b5i gi\u00b6i 2 gi\u00ea 30 ph\u00f3t = 2,5 gi\u00ea Qu\u00b7ng \u00ae\u00f0\u00eang ng\u00f0\u00eai \u00ae\u00e3 \u00ae\u00b7 \u00aei \u00ae\u00f0\u00eec l\u00b5 : 12 \u00d7 2,5 = 30 (km) \u00a7\u00b8p s\u00e8 : 30km. 1 M\u00e9t ca n\u00ab \u00aei v\u00edi v\u00cbn t\u00e8c 15,2 km\/gi\u00ea. T\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang \u00aei \u00ae\u00f0\u00eec c\u00f1a ca n\u00ab trong 3 gi\u00ea. 2 M\u00e9t ng\u00f0\u00eai \u00aei xe \u00ae\u00b9p trong 15 ph\u00f3t v\u00edi v\u00cbn t\u00e8c 12,6 km\/gi\u00ea. T\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang \u00aei \u00ae\u00f0\u00eec c\u00f1a ng\u00f0\u00eai \u00ae\u00e3. 3 M\u00e9t xe m\u00b8y \u00aei t\u00f5 A l\u00f3c 8 gi\u00ea 20 ph\u00f3t v\u00edi v\u00cbn t\u00e8c 42 km\/gi\u00ea, \u00ae\u00d5n B l\u00f3c 11 gi\u00ea. T\u00ddnh \u00ae\u00e9 d\u00b5i qu\u00b7ng \u00ae\u00f0\u00eang AB. Luy\u00d6n t\u00cbp 1 T\u00ddnh \u00ae\u00e9 d\u00b5i qu\u00b7ng \u00ae\u00f0\u00eang v\u00edi \u00ae\u00acn v\u00de l\u00b5 ki-l\u00ab-m\u00d0t r\u00e5i vi\u00d5t v\u00b5o \u00ab tr\u00e8ng : v 32,5 km\/gi\u00ea 210 m\/ph\u00f3t 36 km\/gi\u00ea 40 ph\u00f3t t 4 gi\u00ea 7 ph\u00f3t s 2 M\u00e9t \u00ab t\u00ab \u00aei t\u00f5 A l\u00f3c 7 gi\u00ea 30 ph\u00f3t, \u00ae\u00d5n B l\u00f3c 12 gi\u00ea 15 ph\u00f3t v\u00edi v\u00cbn t\u00e8c 46 km\/gi\u00ea. T\u00ddnh \u00ae\u00e9 d\u00b5i qu\u00b7ng \u00ae\u00f0\u00eang AB. 141","3 Ong m\u00cbt c\u00e3 th\u00d3 bay \u00ae\u00f0\u00eec v\u00edi v\u00cbn t\u00e8c 8 km\/gi\u00ea. T\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang bay \u00ae\u00f0\u00eec c\u00f1a ong m\u00cbt trong 15 ph\u00f3t. 4 K\u00a8ng-gu-ru c\u00e3 th\u00d3 di chuy\u00d3n (v\u00f5a ch\u00b9y v\u00f5a nh\u00b6y) v\u00edi v\u00cbn t\u00e8c 14 m\/gi\u00a9y. T\u00ddnh qu\u00b7ng \u00ae\u00f0\u00eang di chuy\u00d3n \u00ae\u00f0\u00eec c\u00f1a k\u00a8ng-gu-ru trong 1 ph\u00f3t 15 gi\u00a9y. Th\u00eai gian a) B\u00b5i to\u00b8n 1 : M\u00e9t \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang 170km v\u00edi v\u00cbn t\u00e8c 42,5 km\/gi\u00ea. T\u00ddnh th\u00eai gian \u00ab t\u00ab \u00aei qu\u00b7ng \u00ae\u00f0\u00eang \u00ae\u00e3. B\u00b5i gi\u00b6i Th\u00eai gian \u00ab t\u00ab \u00aei l\u00b5 : 170 : 42,5 = 4 (gi\u00ea) \u00a7\u00b8p s\u00e8 : 4 gi\u00ea. Nh\u00cbn x\u00d0t : \u00a7\u00d3 t\u00ddnh th\u00eai gian \u00aei c\u00f1a \u00ab t\u00ab ta l\u00cay qu\u00b7ng \u00ae\u00f0\u00eang \u00aei \u00ae\u00f0\u00eec chia cho qu\u00b7ng \u00ae\u00f0\u00eang \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec trong 1 gi\u00ea hay v\u00cbn t\u00e8c c\u00f1a \u00ab t\u00ab. Mu\u00e8n t\u00ddnh th\u00eai gian ta l\u00cay qu\u00b7ng \u00ae\u00f0\u00eang chia cho v\u00cbn t\u00e8c. Ta c\u00e3 : t = s : v b) B\u00b5i to\u00b8n 2 : M\u00e9t ca n\u00ab \u00aei v\u00edi v\u00cbn t\u00e8c 36 km\/gi\u00ea tr\u00aan qu\u00b7ng \u00ae\u00f0\u00eang s\u00abng d\u00b5i 42km. T\u00ddnh th\u00eai gian \u00aei c\u00f1a ca n\u00ab tr\u00aan qu\u00b7ng \u00ae\u00f0\u00eang \u00ae\u00e3. B\u00b5i gi\u00b6i Th\u00eai gian \u00aei c\u00f1a ca n\u00ab l\u00b5 : 42 : 36 = (gi\u00ea) gi\u00ea = gi\u00ea = 1 gi\u00ea 10 ph\u00f3t \u00a7\u00b8p s\u00e8 : 1 gi\u00ea 10 ph\u00f3t. 142","1 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o \u00ab tr\u00e8ng : s (km) 35 10,35 108,5 81 v (km\/gi\u00ea) 14 4,6 62 36 t (gi\u00ea) 2 a) Tr\u00aan qu\u00b7ng \u00ae\u00f0\u00eang 23,1km, m\u00e9t ng\u00f0\u00eai \u00aei xe \u00ae\u00b9p v\u00edi v\u00cbn t\u00e8c 13,2 km\/gi\u00ea. T\u00ddnh th\u00eai gian \u00aei c\u00f1a ng\u00f0\u00eai \u00ae\u00e3. b) Tr\u00aan qu\u00b7ng \u00ae\u00f0\u00eang 2,5km, m\u00e9t ng\u00f0\u00eai ch\u00b9y v\u00edi v\u00cbn t\u00e8c 10 km\/gi\u00ea. T\u00ddnh th\u00eai gian ch\u00b9y c\u00f1a ng\u00f0\u00eai \u00ae\u00e3. 3 M\u00e9t m\u00b8y bay bay v\u00edi v\u00cbn t\u00e8c 860 km\/gi\u00ea \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang 2150km. H\u00e1i m\u00b8y bay \u00ae\u00d5n n\u00aci l\u00f3c m\u00cay gi\u00ea, n\u00d5u n\u00e3 kh\u00ebi h\u00b5nh l\u00f3c 8 gi\u00ea 45 ph\u00f3t ? Luy\u00d6n t\u00cbp 1 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o \u00ab tr\u00e8ng : s (km) 261 78 165 96 v (km\/gi\u00ea) 60 39 27,5 40 t (gi\u00ea) 2 M\u00e9t con \u00e8c s\u00aan b\u00df v\u00edi v\u00cbn t\u00e8c 12 cm\/ph\u00f3t. H\u00e1i con \u00e8c s\u00aan \u00ae\u00e3 b\u00df \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang 1,08m trong th\u00eai gian bao l\u00a9u ? 3 V\u00cbn t\u00e8c bay c\u00f1a m\u00e9t con chim \u00ae\u00b9i b\u00b5ng l\u00b5 96 km\/gi\u00ea. T\u00ddnh th\u00eai gian \u00ae\u00d3 con \u00ae\u00b9i b\u00b5ng \u00ae\u00e3 bay \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang 72km. 4 M\u00e9t con r\u00b8i c\u00b8 c\u00e3 th\u00d3 b\u00aci v\u00edi v\u00cbn t\u00e8c 420 m\/ph\u00f3t. T\u00ddnh th\u00eai gian \u00ae\u00d3 r\u00b8i c\u00b8 b\u00aci \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang 10,5km. 143","Luy\u00d6n t\u00cbp chung 1 M\u00e9t \u00ab t\u00ab \u00aei qu\u00b7ng \u00ae\u00f0\u00eang 135km h\u00d5t 3 gi\u00ea. M\u00e9t xe m\u00b8y c\u00f2ng \u00aei qu\u00b7ng \u00ae\u00f0\u00eang \u00ae\u00e3 h\u00d5t 4 gi\u00ea 30 ph\u00f3t. H\u00e1i m\u00e7i gi\u00ea \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec nhi\u00d2u h\u00acn xe m\u00b8y bao nhi\u00aau ki-l\u00ab-m\u00d0t ? 2 M\u00e9t xe m\u00b8y \u00aei qua chi\u00d5c c\u00c7u d\u00b5i 1250m h\u00d5t 2 ph\u00f3t. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a xe m\u00b8y v\u00edi \u00ae\u00acn v\u00de \u00aeo l\u00b5 km\/gi\u00ea. 3 M\u00e9t xe ng\u00f9a \u00aei qu\u00b7ng \u00ae\u00f0\u00eang 15,75km h\u00d5t 1 gi\u00ea 45 ph\u00f3t. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a xe ng\u00f9a v\u00edi \u00ae\u00acn v\u00de \u00aeo l\u00b5 m\/ph\u00f3t. 4 Lo\u00b5i c\u00b8 heo c\u00e3 th\u00d3 b\u00aci v\u00edi v\u00cbn t\u00e8c 72 km\/gi\u00ea. H\u00e1i v\u00edi v\u00cbn t\u00e8c \u00ae\u00e3, c\u00b8 heo b\u00aci 2400m h\u00d5t bao nhi\u00aau ph\u00f3t ? Luy\u00d6n t\u00cbp chung 1 a) Qu\u00b7ng \u00ae\u00f0\u00eang AB d\u00b5i 180km. M\u00e9t \u00ab t\u00ab \u00aei t\u00f5 A \u00ae\u00d5n B v\u00edi v\u00cbn t\u00e8c 54 km\/gi\u00ea, c\u00efng l\u00f3c \u00ae\u00e3 m\u00e9t xe m\u00b8y \u00aei t\u00f5 B \u00ae\u00d5n A v\u00edi v\u00cbn t\u00e8c 36 km\/gi\u00ea. H\u00e1i k\u00d3 t\u00f5 l\u00f3c b\u00bet \u00ae\u00c7u \u00aei, sau m\u00cay gi\u00ea \u00ab t\u00ab g\u00c6p xe m\u00b8y ? \u00a4 t\u00ab 180km Xe m\u00b8y A B 144","H\u00f0\u00edng d\u00c9n : Sau m\u00e7i gi\u00ea, c\u00b6 \u00ab t\u00ab v\u00b5 xe m\u00b8y \u00aei \u00ae\u00f0\u00eec qu\u00b7ng \u00ae\u00f0\u00eang l\u00b5 : 54 + 36 = 90 (km) Th\u00eai gian \u00aei \u00ae\u00d3 \u00ab t\u00ab g\u00c6p xe m\u00b8y l\u00b5 : 180 : 90 = 2 (gi\u00ea) b) Qu\u00b7ng \u00ae\u00f0\u00eang AB d\u00b5i 276km. Hai \u00ab t\u00ab kh\u00ebi h\u00b5nh c\u00efng m\u00e9t l\u00f3c, m\u00e9t xe \u00aei t\u00f5 A \u00ae\u00d5n B v\u00edi v\u00cbn t\u00e8c 42 km\/gi\u00ea, m\u00e9t xe \u00aei t\u00f5 B \u00ae\u00d5n A v\u00edi v\u00cbn t\u00e8c 50 km\/gi\u00ea. H\u00e1i k\u00d3 t\u00f5 l\u00f3c b\u00bet \u00ae\u00c7u \u00aei, sau m\u00cay gi\u00ea hai \u00ab t\u00ab g\u00c6p nhau ? 2 M\u00e9t ca n\u00ab \u00aei t\u00f5 A \u00ae\u00d5n B v\u00edi v\u00cbn t\u00e8c 12 km\/gi\u00ea. Ca n\u00ab kh\u00ebi h\u00b5nh l\u00f3c 7 gi\u00ea 30 ph\u00f3t v\u00b5 \u00ae\u00d5n B l\u00f3c 11 gi\u00ea 15 ph\u00f3t. T\u00ddnh \u00ae\u00e9 d\u00b5i qu\u00b7ng \u00ae\u00f0\u00eang AB. 3 M\u00e9t con ng\u00f9a ch\u00b9y \u00aeua tr\u00aan qu\u00b7ng \u00ae\u00f0\u00eang 15km h\u00d5t 20 ph\u00f3t. T\u00ddnh v\u00cbn t\u00e8c c\u00f1a con ng\u00f9a \u00ae\u00e3 v\u00edi \u00ae\u00acn v\u00de \u00aeo l\u00b5 m\/ph\u00f3t. 4 Hai th\u00b5nh ph\u00e8 A v\u00b5 B c\u00b8ch nhau 135km. M\u00e9t xe m\u00b8y \u00aei t\u00f5 A \u00ae\u00d5n B v\u00edi v\u00cbn t\u00e8c 42 km\/gi\u00ea. H\u00e1i sau khi kh\u00ebi h\u00b5nh 2 gi\u00ea 30 ph\u00f3t xe m\u00b8y c\u00dfn c\u00b8ch B bao nhi\u00aau ki- l\u00ab-m\u00d0t ? Luy\u00d6n t\u00cbp chung 1 a) M\u00e9t ng\u00f0\u00eai \u00aei xe \u00ae\u00b9p t\u00f5 B \u00ae\u00d5n C v\u00edi v\u00cbn t\u00e8c 12 km\/gi\u00ea, c\u00efng l\u00f3c \u00ae\u00e3 m\u00e9t ng\u00f0\u00eai \u00aei xe m\u00b8y t\u00f5 A c\u00b8ch B l\u00b5 48km v\u00edi v\u00cbn t\u00e8c 36 km\/gi\u00ea v\u00b5 \u00aeu\u00e6i theo xe \u00ae\u00b9p (xem h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y). H\u00e1i k\u00d3 t\u00f5 l\u00f3c b\u00bet \u00ae\u00c7u \u00aei, sau m\u00cay gi\u00ea xe m\u00b8y \u00aeu\u00e6i k\u00dep xe \u00ae\u00b9p ? H\u00f0\u00edng d\u00c9n : Sau m\u00e7i gi\u00ea xe m\u00b8y g\u00c7n xe \u00ae\u00b9p l\u00b5 : Xe m\u00b8y Xe \u00ae\u00b9p AB C 48km 36 \u2212 12 = 24 (km) Th\u00eai gian \u00aei \u00ae\u00d3 xe m\u00b8y \u00aeu\u00e6i k\u00dep xe \u00ae\u00b9p l\u00b5 : 48 : 24 = 2 (gi\u00ea) 145","b) M\u00e9t ng\u00f0\u00eai \u00aei xe \u00ae\u00b9p t\u00f5 A \u00ae\u00d5n B v\u00edi v\u00cbn t\u00e8c 12 km\/gi\u00ea. Sau 3 gi\u00ea m\u00e9t xe m\u00b8y c\u00f2ng \u00aei t\u00f5 A \u00ae\u00d5n B v\u00edi v\u00cbn t\u00e8c 36 km\/gi\u00ea. H\u00e1i k\u00d3 t\u00f5 l\u00f3c xe m\u00b8y b\u00bet \u00ae\u00c7u \u00aei, sau bao l\u00a9u xe m\u00b8y \u00aeu\u00e6i k\u00dep xe \u00ae\u00b9p ? 2 Lo\u00b5i b\u00b8o g\u00cam c\u00e3 th\u00d3 ch\u00b9y v\u00edi v\u00cbn t\u00e8c 120 km\/gi\u00ea. H\u00e1i v\u00edi v\u00cbn t\u00e8c \u00ae\u00e3 b\u00b8o g\u00cam ch\u00b9y trong gi\u00ea \u00ae\u00f0\u00eec bao nhi\u00aau ki-l\u00ab-m\u00d0t ? 3 M\u00e9t xe m\u00b8y \u00aei t\u00f5 A l\u00f3c 8 gi\u00ea 37 ph\u00f3t v\u00edi v\u00cbn t\u00e8c 36 km\/gi\u00ea. \u00a7\u00d5n 11 gi\u00ea 7 ph\u00f3t m\u00e9t \u00ab t\u00ab c\u00f2ng \u00aei t\u00f5 A \u00aeu\u00e6i theo xe m\u00b8y v\u00edi v\u00cbn t\u00e8c 54 km\/gi\u00ea. H\u00e1i \u00ab t\u00ab \u00aeu\u00e6i k\u00dep xe m\u00b8y l\u00f3c m\u00cay gi\u00ea ? 146","Ch\u00f0\u00acng n\u00a8m \u00a4n t\u00cbp I - \u00abn t\u00cbp v\u00d2 s\u00e8 t\u00f9 nhi\u00aan, ph\u00a9n s\u00e8, s\u00e8 th\u00cbp ph\u00a9n, s\u00e8 \u00aeo \u00ae\u00b9i l\u00f0\u00eeng \u00a4n t\u00cbp v\u00d2 s\u00e8 t\u00f9 nhi\u00aan 1 a) \u00a7\u00e4c c\u00b8c s\u00e8 : 975 806 ; 5 723 600 ; 472 036 953. 70 815 ; 66 665 ; ... ; 66 667. b) N\u00aau gi\u00b8 tr\u00de c\u00f1a ch\u00f7 s\u00e8 5 trong m\u00e7i s\u00e8 tr\u00aan. ... ; 3 000 ; 3 002. ... ; 2 001 ; 2 003. 2 Vi\u00d5t s\u00e8 th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam \u00ae\u00d3 c\u00e3 : a) Ba s\u00e8 t\u00f9 nhi\u00aan li\u00aan ti\u00d5p : 998 ; 999 ; ... . ... ; 8000 ; 8001. b) Ba s\u00e8 ch\u00bdn li\u00aan ti\u00d5p : 98 ; ... ; 102. 996 ; ... ; ... . c) Ba s\u00e8 l\u00ce li\u00aan ti\u00d5p : 299 ; ... ; 303. 77 ; 79 ; ... . 3> 1000 ... 997 53 796 ... 53 800 6987 ... 10 087 217 690 ... 217 689 <? 7500 : 10 ... 750 68 400 ... 684 \u00d7 100 = 4 Vi\u00d5t c\u00b8c s\u00e8 sau theo th\u00f8 t\u00f9 : a) T\u00f5 b\u00d0 \u00ae\u00d5n l\u00edn : 4856 ; 3999 ; 5486 ; 5468. b) T\u00f5 l\u00edn \u00ae\u00d5n b\u00d0 : 2763 ; 2736 ; 3726 ; 3762. 147","5 T\u00d7m ch\u00f7 s\u00e8 th\u00ddch h\u00eep \u00ae\u00d3 khi vi\u00d5t v\u00b5o \u00ab tr\u00e8ng ta \u00ae\u00f0\u00eec : a) 43 chia h\u00d5t cho 3 ; b) 2 7 chia h\u00d5t cho 9 ; c) 81 chia h\u00d5t cho c\u00b6 2 v\u00b5 5 ; d) 46 chia h\u00d5t cho c\u00b6 3 v\u00b5 5. \u00a4n t\u00cbp v\u00d2 ph\u00a9n s\u00e8 1 a) Vi\u00d5t ph\u00a9n s\u00e8 ch\u00d8 ph\u00c7n \u00ae\u00b7 t\u00ab m\u00b5u c\u00f1a m\u00e7i h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y : H\u00d7nh 1 H\u00d7nh 2 H\u00d7nh 3 H\u00d7nh 4 b) Vi\u00d5t h\u00e7n s\u00e8 ch\u00d8 ph\u00c7n \u00ae\u00b7 t\u00ab m\u00b5u c\u00f1a m\u00e7i h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y : H\u00d7nh 1 H\u00d7nh 2 H\u00d7nh 3 H\u00d7nh 4 2 R\u00f3t g\u00e4n c\u00b8c ph\u00a9n s\u00e8 : . 148","3 Quy \u00ae\u00e5ng m\u00c9u s\u00e8 c\u00b8c ph\u00a9n s\u00e8 : a) v\u00b5 ; b) v\u00b5 ; c) , v\u00b5 . ... . 4> ... ... <? = 5 Vi\u00d5t ph\u00a9n s\u00e8 th\u00ddch h\u00eep v\u00b5o v\u00b9ch \u00eb gi\u00f7a v\u00b5 tr\u00aan tia s\u00e8 : 12 0 331 \u00a4n t\u00cbp v\u00d2 ph\u00a9n s\u00e8 (ti\u00d5p theo) 1 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : Ph\u00a9n s\u00e8 ch\u00d8 ph\u00c7n \u00ae\u00b7 t\u00ab m\u00b5u c\u00f1a b\u00a8ng gi\u00cay l\u00b5 : A. B. C. D. 2 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : C\u00e3 20 vi\u00aan bi, trong \u00ae\u00e3 c\u00e3 3 vi\u00aan bi n\u00a9u, 4 vi\u00aan bi xanh, 5 vi\u00aan bi \u00ae\u00e1, 8 vi\u00aan bi v\u00b5ng. Nh\u00f0 v\u00cby, s\u00e8 vi\u00aan bi c\u00e3 m\u00b5u : A. N\u00a9u B. \u00a7\u00e1 C. Xanh D. V\u00b5ng 149"]