Toan_5

["","","","","","","","","","","","","CM YK Tr.62 3 Mua 5kg \u00ae\u00f0\u00eang ph\u00b6i tr\u00b6 38 500 \u00ae\u00e5ng. H\u00e1i mua 3,5kg \u00ae\u00f0\u00eang c\u00efng lo\u00b9i ph\u00b6i tr\u00b6 \u00ddt h\u00acn bao nhi\u00aau ti\u00d2n ? 4 a) T\u00ddnh r\u00e5i so s\u00b8nh gi\u00b8 tr\u00de c\u00f1a (a + b) \u00d7 c v\u00b5 a \u00d7 c + b \u00d7 c : a b c (a + b) \u00d7 c a\u00d7c+b\u00d7c 2,4 3,8 1,2 6,5 2,7 0,8 Nh\u00cbn x\u00d0t : (a + b) \u00d7 c = a \u00d7 c + b \u00d7 c b) T\u00ddnh b\u00bbng c\u00b8ch thu\u00cbn ti\u00d6n nh\u00cat : 7,8 \u00d7 0,35 + 0,35 \u00d7 2,2. 9,3 \u00d7 6,7 + 9,3 \u00d7 3,3 ; Luy\u00d6n t\u00cbp chung 1 T\u00ddnh : b) 7,7 + 7,3 \u00d7 7,4. a) 375,84 \u2013 95,69 + 36,78 ; 2 T\u00ddnh b\u00bbng hai c\u00b8ch : b) (9,6 \u2212 4,2) \u00d7 3,6. a) (6,75 + 3,25) \u00d7 4,2 ; 3 a) T\u00ddnh b\u00bbng c\u00b8ch thu\u00cbn ti\u00d6n nh\u00cat : 4,7 \u00d7 5,5 \u2212 4,7 \u00d7 4,5. 0,12 \u00d7 400 ; 9,8 \u00d7 x = 6,2 \u00d7 9,8. b) T\u00ddnh nh\u00c8m k\u00d5t qu\u00b6 t\u00d7m x : 5,4 \u00d7 x = 5,4 ; 4 Mua 4m v\u00b6i ph\u00b6i tr\u00b6 60 000 \u00ae\u00e5ng. H\u00e1i mua 6,8m v\u00b6i c\u00efng lo\u00b9i ph\u00b6i tr\u00b6 nhi\u00d2u h\u00acn bao nhi\u00aau ti\u00d2n ? 62","CM YK Tr.63 4. Ph\u00d0p chia Chia m\u00e9t s\u00e8 th\u00cbp ph\u00a9n cho m\u00e9t s\u00e8 t\u00f9 nhi\u00aan a) V\u00dd d\u00f4 1 : M\u00e9t s\u00eei d\u00a9y d\u00b5i 8,4m \u00ae\u00f0\u00eec chia th\u00b5nh 4 \u00aeo\u00b9n b\u00bbng nhau. H\u00e1i m\u00e7i \u00aeo\u00b9n d\u00a9y d\u00b5i bao nhi\u00aau m\u00d0t ? ?m 8,4m Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p chia : 8,4 : 4 = ? (m) Ta c\u00e3 : 8,4m = 84dm 84 4 04 21 (dm) 0 21dm = 2,1m V\u00cby : 8,4 : 4 = 2,1 (m). Th\u00abng th\u00f0\u00eang ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m nh\u00f0 sau : 8,4 4 G 8 chia 4 \u00ae\u00f0\u00eec 2, vi\u00d5t 2 ; 0 4 2,1 (m) 2 nh\u00a9n 4 b\u00bbng 8 ; 8 tr\u00f5 8 b\u00bbng 0, vi\u00d5t 0. 0 G Vi\u00d5t d\u00cau ph\u00c8y v\u00b5o b\u00aan ph\u00b6i 2. G H\u00b9 4 ; 4 chia 4 \u00ae\u00f0\u00eec 1, vi\u00d5t 1 ; 1 nh\u00a9n 4 b\u00bbng 4 ; 4 tr\u00f5 4 b\u00bbng 0, vi\u00d5t 0. 63","CM YK Tr.64 b) V\u00dd d\u00f4 2 : 72,58 : 19 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m t\u00f0\u00acng t\u00f9 nh\u00f0 v\u00dd d\u00f4 1 : 19 3,82 Mu\u00e8n chia m\u00e9t s\u00e8 th\u00cbp ph\u00a9n cho m\u00e9t s\u00e8 t\u00f9 nhi\u00aan ta l\u00b5m nh\u00f0 sau : \u2212 Chia ph\u00c7n nguy\u00aan c\u00f1a s\u00e8 b\u00de chia cho s\u00e8 chia. \u2212 Vi\u00d5t d\u00cau ph\u00c8y v\u00b5o b\u00aan ph\u00b6i th\u00f0\u00acng \u00ae\u00b7 t\u00d7m \u00ae\u00f0\u00eec tr\u00f0\u00edc khi l\u00cay ch\u00f7 s\u00e8 \u00ae\u00c7u ti\u00aan \u00eb ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 b\u00de chia \u00ae\u00d3 ti\u00d5p t\u00f4c th\u00f9c hi\u00d6n ph\u00d0p chia. \u2212 Ti\u00d5p t\u00f4c chia v\u00edi t\u00f5ng ch\u00f7 s\u00e8 \u00eb ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 b\u00de chia. 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : b) 95,2 : 68 ; a) 5,28 : 4 ; d) 75,52 : 32. c) 0,36 : 9 ; 2 T\u00d7m x : b) 5 \u00d7 x = 0,25. a) x \u00d7 3 = 8,4 ; 3 M\u00e9t ng\u00f0\u00eai \u00aei xe m\u00b8y trong 3 gi\u00ea \u00aei \u00ae\u00f0\u00eec 126,54km. H\u00e1i trung b\u00d7nh m\u00e7i gi\u00ea ng\u00f0\u00eai \u00ae\u00e3 \u00aei \u00ae\u00f0\u00eec bao nhi\u00aau ki-l\u00ab-m\u00d0t ? Luy\u00d6n t\u00cbp 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : a) 67,2 : 7 ; b) 3,44 : 4 ; c) 42,7 : 7 ; d) 46,827 : 9. 2 a) 22,44 18 Trong ph\u00d0p chia n\u00b5y, th\u00f0\u00acng l\u00b5 1,24, 4 4 1,24 s\u00e8 d\u00f0 l\u00b5 0,12. 84 12 Th\u00f6 l\u00b9i : 1,24 \u00d7 18 + 0,12 = 22,44. 64","CM YK Tr.65 b) T\u00d7m s\u00e8 d\u00f0 c\u00f1a ph\u00d0p chia sau : 43,19 21 1 19 2,05 14 3 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : b) 12,24 : 20. a) 26,5 : 25 ; Ch\u00f3 \u00fd : Khi chia s\u00e8 th\u00cbp ph\u00a9n cho s\u00e8 t\u00f9 nhi\u00aan m\u00b5 c\u00dfn d\u00f0, ta c\u00e3 th\u00d3 chia ti\u00d5p b\u00bbng c\u00b8ch : vi\u00d5t th\u00aam ch\u00f7 s\u00e8 0 v\u00b5o b\u00aan ph\u00b6i s\u00e8 d\u00f0 r\u00e5i ti\u00d5p t\u00f4c chia. Ch\u00bcng h\u00b9n : 5 4,26 4 C\u00e3 8 bao g\u00b9o c\u00a9n n\u00c6ng 243,2kg. H\u00e1i 12 bao g\u00b9o nh\u00f0 th\u00d5 c\u00a9n n\u00c6ng bao nhi\u00aau ki-l\u00ab-gam ? Chia m\u00e9t s\u00e8 th\u00cbp ph\u00a9n cho 10, 100, 1000, ... a) V\u00dd d\u00f4 1 : 213,8 : 10 = ? 10 Nh\u00cbn x\u00d0t : 21,38 N\u00d5u chuy\u00d3n d\u00cau ph\u00c8y c\u00f1a s\u00e8 213,8 sang b\u00aan tr\u00b8i m\u00e9t ch\u00f7 s\u00e8 ta c\u00f2ng \u00ae\u00f0\u00eec 21,38. 213,8 : 10 = 21,38 65","CM YK Tr.66 b) V\u00dd d\u00f4 2 : 89,13 : 100 = ? 100 0,8913 Nh\u00cbn x\u00d0t : N\u00d5u chuy\u00d3n d\u00cau ph\u00c8y c\u00f1a s\u00e8 89,13 sang b\u00aan tr\u00b8i hai ch\u00f7 s\u00e8 ta c\u00f2ng \u00ae\u00f0\u00eec 0,8913. 89,13 : 100 = 0,8913 Mu\u00e8n chia m\u00e9t s\u00e8 th\u00cbp ph\u00a9n cho 10, 100, 1000, ... ta ch\u00d8 vi\u00d6c chuy\u00d3n d\u00cau ph\u00c8y c\u00f1a s\u00e8 \u00ae\u00e3 l\u00c7n l\u00f0\u00eet sang b\u00aan tr\u00b8i m\u00e9t, hai, ba, ... ch\u00f7 s\u00e8. 1 T\u00ddnh nh\u00c8m : 0,65 : 10 ; 432,9 : 100 ; 13,96 : 1000. a) 43,2 : 10 ; 2,07 : 10 ; 2,23 : 100 ; 999,8 : 1000. b) 23,7 : 10 ; 2 T\u00ddnh nh\u00c8m r\u00e5i so s\u00b8nh k\u00d5t qu\u00b6 t\u00ddnh : a) 12,9 : 10 v\u00b5 12,9 \u00d7 0,1 ; b) 123,4 : 100 v\u00b5 123,4 \u00d7 0,01 ; c) 5,7 : 10 v\u00b5 5,7 \u00d7 0,1 ; d) 87,6 : 100 v\u00b5 87,6 \u00d7 0,01. 3 M\u00e9t kho g\u00b9o c\u00e3 537,25 t\u00can g\u00b9o. Ng\u00f0\u00eai ta \u00ae\u00b7 l\u00cay ra s\u00e8 g\u00b9o trong kho. H\u00e1i trong kho c\u00dfn l\u00b9i bao nhi\u00aau t\u00can g\u00b9o ? 66","CM YK Tr.67 chia m\u00e9t s\u00e8 t\u00f9 nhi\u00aan cho m\u00e9t s\u00e8 t\u00f9 nhi\u00aan m\u00b5 th\u00f0\u00acng t\u00d7m \u00ae\u00f0\u00eec l\u00b5 m\u00e9t s\u00e8 th\u00cbp ph\u00a9n a) V\u00dd d\u00f4 1 : M\u00e9t c\u00b8i s\u00a9n h\u00d7nh vu\u00abng c\u00e3 chu vi 27m. H\u00e1i c\u00b9nh c\u00f1a s\u00a9n d\u00b5i bao nhi\u00aau m\u00d0t ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p chia : 27 : 4 = ? (m) Th\u00abng th\u00f0\u00eang ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m nh\u00f0 sau : 27 4 G 27 chia 4 \u00ae\u00f0\u00eec 6, vi\u00d5t 6 ; 30 6,75 (m) 20 6 nh\u00a9n 4 b\u00bbng 24 ; 27 tr\u00f5 24 b\u00bbng 3, vi\u00d5t 3. G \u00a7\u00d3 chia ti\u00d5p, ta vi\u00d5t d\u00cau ph\u00c8y v\u00b5o b\u00aan ph\u00b6i 6 v\u00b5 vi\u00d5t th\u00aam ch\u00f7 s\u00e8 0 v\u00b5o b\u00aan ph\u00b6i 3 \u00ae\u00f0\u00eec 30. 0 30 chia 4 \u00ae\u00f0\u00eec 7, vi\u00d5t 7 ; 7 nh\u00a9n 4 b\u00bbng 28 ; 30 tr\u00f5 28 b\u00bbng 2, vi\u00d5t 2. G Vi\u00d5t th\u00aam ch\u00f7 s\u00e8 0 v\u00b5o b\u00aan ph\u00b6i 2 \u00ae\u00f0\u00eec 20 ; 20 chia 4 \u00ae\u00f0\u00eec 5, vi\u00d5t 5 ; 5 nh\u00a9n 4 b\u00bbng 20 ; 20 tr\u00f5 20 b\u00bbng 0, vi\u00d5t 0. V\u00cby : 27 : 4 = 6,75 (m). b) V\u00dd d\u00f4 2 : 43 : 52 = ? Ph\u00d0p chia n\u00b5y c\u00e3 s\u00e8 b\u00de chia 43 b\u00d0 h\u00acn s\u00e8 chia 52, ta c\u00e3 th\u00d3 l\u00b5m nh\u00f0 sau : 43,0 52 G Chuy\u00d3n 43 th\u00b5nh 43,0. 1 40 0,82 G \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh nh\u00f0 ph\u00d0p chia 43,0 : 52 36 (chia s\u00e8 th\u00cbp ph\u00a9n cho s\u00e8 t\u00f9 nhi\u00aan). Khi chia m\u00e9t s\u00e8 t\u00f9 nhi\u00aan cho m\u00e9t s\u00e8 t\u00f9 nhi\u00aan m\u00b5 c\u00dfn d\u00f0, ta ti\u00d5p t\u00f4c chia nh\u00f0 sau : \u2212 Vi\u00d5t d\u00cau ph\u00c8y v\u00b5o b\u00aan ph\u00b6i s\u00e8 th\u00f0\u00acng. \u2212 Vi\u00d5t th\u00aam v\u00b5o b\u00aan ph\u00b6i s\u00e8 d\u00f0 m\u00e9t ch\u00f7 s\u00e8 0 r\u00e5i chia ti\u00d5p. \u2212 N\u00d5u c\u00dfn d\u00f0 n\u00f7a, ta l\u00b9i vi\u00d5t th\u00aam v\u00b5o b\u00aan ph\u00b6i s\u00e8 d\u00f0 m\u00edi m\u00e9t ch\u00f7 s\u00e8 0 r\u00e5i ti\u00d5p t\u00f4c chia, v\u00b5 c\u00e3 th\u00d3 c\u00f8 l\u00b5m nh\u00f0 th\u00d5 m\u00b7i. 67","CM YK Tr.68 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : b) 15 : 8 a) 12 : 5 75 : 12 23 : 4 81 : 4 882 : 36 2 May 25 b\u00e9 qu\u00c7n \u00b8o nh\u00f0 nhau h\u00d5t 70m v\u00b6i. H\u00e1i may 6 b\u00e9 qu\u00c7n \u00b8o nh\u00f0 th\u00d5 h\u00d5t bao nhi\u00aau m\u00d0t v\u00b6i ? 3 Vi\u00d5t c\u00b8c ph\u00a9n s\u00e8 sau d\u00f0\u00edi d\u00b9ng s\u00e8 th\u00cbp ph\u00a9n : . luy\u00d6n t\u00cbp 1 T\u00ddnh : b) 35,04 : 4 \u2212 6,87 ; a) 5,9 : 2 + 13,06 ; d) 8,76 \u00d7 4 : 8. c) 167 : 25 : 4 ; 2 T\u00ddnh r\u00e5i so s\u00b8nh k\u00d5t qu\u00b6 t\u00ddnh : a) 8,3 \u00d7 0,4 v\u00b5 8,3 \u00d7 10 : 25 ; b) 4,2 \u00d7 1,25 v\u00b5 4,2 \u00d7 10 : 8 ; c) 0,24 \u00d7 2,5 v\u00b5 0,24 \u00d7 10 : 4. 3 M\u00e9t m\u00b6nh v\u00f0\u00ean h\u00d7nh ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 24m, chi\u00d2u r\u00e9ng b\u00bbng chi\u00d2u d\u00b5i. T\u00ddnh chu vi v\u00b5 di\u00d6n t\u00ddch c\u00f1a m\u00b6nh v\u00f0\u00ean \u00ae\u00e3. 4 Trong 3 gi\u00ea xe m\u00b8y \u00aei \u00ae\u00f0\u00eec 93km. Trong 2 gi\u00ea \u00ab t\u00ab \u00aei \u00ae\u00f0\u00eec 103km. H\u00e1i m\u00e7i gi\u00ea \u00ab t\u00ab \u00aei nhi\u00d2u h\u00acn xe m\u00b8y bao nhi\u00aau ki-l\u00ab-m\u00d0t ? 68","CM YK Tr.69 chia m\u00e9t s\u00e8 t\u00f9 nhi\u00aan cho m\u00e9t s\u00e8 th\u00cbp ph\u00a9n a) T\u00ddnh r\u00e5i so s\u00b8nh k\u00d5t qu\u00b6 t\u00ddnh : G 25 : 4 v\u00b5 (25 \u00d7 5) : (4 \u00d7 5). G 4,2 : 7 v\u00b5 (4,2 \u00d7 10) : (7 \u00d7 10). G 37,8 : 9 v\u00b5 (37,8 \u00d7 100) : (9 \u00d7 100). Khi nh\u00a9n s\u00e8 b\u00de chia v\u00b5 s\u00e8 chia v\u00edi c\u00efng m\u00e9t s\u00e8 kh\u00b8c 0 th\u00d7 th\u00f0\u00acng kh\u00abng thay \u00ae\u00e6i. b) V\u00dd d\u00f4 1 : M\u00e9t m\u00b6nh v\u00f0\u00ean h\u00d7nh ch\u00f7 nh\u00cbt c\u00e3 di\u00d6n t\u00ddch 57m2, chi\u00d2u d\u00b5i 9,5m. H\u00e1i chi\u00d2u r\u00e9ng c\u00f1a m\u00b6nh v\u00f0\u00ean l\u00b5 bao nhi\u00aau m\u00d0t ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p chia : 57 : 9,5 = ? (m) Ta c\u00e3 : 57 : 9,5 = (57 \u00d7 10 ) : (9,5 \u00d7 10) 57 : 9,5 = 570 : 95 Th\u00abng th\u00f0\u00eang ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m nh\u00f0 sau : 570 9,5 G Ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 9,5 (s\u00e8 chia) c\u00e3 m\u00e9t ch\u00f7 s\u00e8. 0 6 (m) G Vi\u00d5t th\u00aam m\u00e9t ch\u00f7 s\u00e8 0 v\u00b5o b\u00aan ph\u00b6i 57(s\u00e8 b\u00de chia) \u00ae\u00f0\u00eec 570 ; b\u00e1 d\u00cau ph\u00c8y \u00eb s\u00e8 9,5 \u00ae\u00f0\u00eec 95. G Th\u00f9c hi\u00d6n ph\u00d0p chia 570 : 95. V\u00cby : 57 : 9,5 = 6 (m). c) V\u00dd d\u00f4 2 : 99 : 8,25 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m nh\u00f0 sau : 9900 8,25 G Ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 8,25 c\u00e3 hai ch\u00f7 s\u00e8. 1650 12 G Vi\u00d5t th\u00aam hai ch\u00f7 s\u00e8 0 v\u00b5o b\u00aan ph\u00b6i 99 \u00ae\u00f0\u00eec 9900 ; b\u00e1 d\u00cau ph\u00c8y \u00eb 8,25 \u00ae\u00f0\u00eec 825. 0 G Th\u00f9c hi\u00d6n ph\u00d0p chia 9900 : 825. Mu\u00e8n chia m\u00e9t s\u00e8 t\u00f9 nhi\u00aan cho m\u00e9t s\u00e8 th\u00cbp ph\u00a9n ta l\u00b5m nh\u00f0 sau : \u2212 \u00a7\u00d5m xem c\u00e3 bao nhi\u00aau ch\u00f7 s\u00e8 \u00eb ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 chia th\u00d7 vi\u00d5t th\u00aam v\u00b5o b\u00aan ph\u00b6i s\u00e8 b\u00de chia b\u00cay nhi\u00aau ch\u00f7 s\u00e8 0. \u2212 B\u00e1 d\u00cau ph\u00c8y \u00eb s\u00e8 chia r\u00e5i th\u00f9c hi\u00d6n ph\u00d0p chia nh\u00f0 chia c\u00b8c s\u00e8 t\u00f9 nhi\u00aan. 69","CM YK Tr.70 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : b) 702 : 7,2 ; a) 7 : 3,5 ; d) 2 : 12,5. c) 9 : 4,5 ; 2 T\u00ddnh nh\u00c8m : b) 168 : 0,1 c) 934 : 0,01 a) 32 : 0,1 168 : 10 934 : 100 32 : 10 3 M\u00e9t thanh s\u00bet d\u00b5i 0,8m c\u00a9n n\u00c6ng 16kg. H\u00e1i m\u00e9t thanh s\u00bet c\u00efng lo\u00b9i d\u00b5i 0,18m c\u00a9n n\u00c6ng bao nhi\u00aau ki-l\u00ab-gam ? luy\u00d6n t\u00cbp 1 T\u00ddnh r\u00e5i so s\u00b8nh k\u00d5t qu\u00b6 t\u00ddnh : b) 3 : 0,2 v\u00b5 3 \u00d7 5 a) 5 : 0,5 v\u00b5 5 \u00d7 2 18 : 0,25 v\u00b5 18 \u00d7 4 52 : 0,5 v\u00b5 52 \u00d7 2 2 T\u00d7m x : b) 9,5 \u00d7 x = 399. a) x \u00d7 8,6 = 387 ; 3 Th\u00efng to c\u00e3 21l d\u00c7u, th\u00efng b\u00d0 c\u00e3 15l d\u00c7u. S\u00e8 d\u00c7u \u00ae\u00e3 \u00ae\u00f0\u00eec ch\u00f8a v\u00b5o c\u00b8c chai nh\u00f0 nhau, m\u00e7i chai c\u00e3 0,75l. H\u00e1i c\u00e3 t\u00cat c\u00b6 bao nhi\u00aau chai d\u00c7u ? 4 M\u00e9t th\u00f6a ru\u00e9ng h\u00d7nh ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u r\u00e9ng 12,5m v\u00b5 c\u00e3 di\u00d6n t\u00ddch b\u00bbng di\u00d6n t\u00ddch h\u00d7nh vu\u00abng c\u00b9nh 25m. T\u00ddnh chu vi th\u00f6a ru\u00e9ng h\u00d7nh ch\u00f7 nh\u00cbt \u00ae\u00e3. 70","CM YK Tr.71 Chia m\u00e9t s\u00e8 th\u00cbp ph\u00a9n cho m\u00e9t s\u00e8 th\u00cbp ph\u00a9n a) V\u00dd d\u00f4 1 : M\u00e9t thanh s\u00bet d\u00b5i 6,2dm c\u00a9n n\u00c6ng 23,56kg. H\u00e1i 1dm c\u00f1a thanh s\u00bet \u00ae\u00e3 c\u00a9n n\u00c6ng bao nhi\u00aau ki-l\u00ab-gam ? Ta ph\u00b6i th\u00f9c hi\u00d6n ph\u00d0p chia : 23,56 : 6,2 = ? (kg) Ta c\u00e3 : 23,56 : 6,2 = (23,56 \u00d7 10) : (6,2 \u00d7 10) 23,56 : 6,2 = 235,6 : 62 Th\u00abng th\u00f0\u00eang ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m nh\u00f0 sau : G Ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 6,2 c\u00e3 m\u00e9t ch\u00f7 s\u00e8. 23,5,6 6,2 G Chuy\u00d3n d\u00cau ph\u00c8y c\u00f1a s\u00e8 23,56 sang b\u00aan ph\u00b6i 4 9 6 3,8 (kg) m\u00e9t ch\u00f7 s\u00e8 \u00ae\u00f0\u00eec 235,6 ; b\u00e1 d\u00cau ph\u00c8y \u00eb s\u00e8 6,2 0 \u00ae\u00f0\u00eec 62. G Th\u00f9c hi\u00d6n ph\u00d0p chia 235,6 : 62. V\u00cby : 23,56 : 6,2 = 3,8 (kg). b) V\u00dd d\u00f4 2 : 82,55 : 1,27 = ? Ta \u00ae\u00c6t t\u00ddnh r\u00e5i l\u00b5m nh\u00f0 sau : G Ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a hai s\u00e8 82,55 v\u00b5 1,27 1,27 c\u00efng c\u00e3 hai ch\u00f7 s\u00e8 ; b\u00e1 d\u00cau ph\u00c8y \u00eb hai s\u00e8 \u00ae\u00e3 65 \u00ae\u00f0\u00eec 8255 v\u00b5 127. G Th\u00f9c hi\u00d6n ph\u00d0p chia 8255 : 127. Mu\u00e8n chia m\u00e9t s\u00e8 th\u00cbp ph\u00a9n cho m\u00e9t s\u00e8 th\u00cbp ph\u00a9n ta l\u00b5m nh\u00f0 sau : \u2212 \u00a7\u00d5m xem c\u00e3 bao nhi\u00aau ch\u00f7 s\u00e8 \u00eb ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a s\u00e8 chia th\u00d7 chuy\u00d3n d\u00cau ph\u00c8y \u00eb s\u00e8 b\u00de chia sang b\u00aan ph\u00b6i b\u00cay nhi\u00aau ch\u00f7 s\u00e8. \u2212 B\u00e1 d\u00cau ph\u00c8y \u00eb s\u00e8 chia r\u00e5i th\u00f9c hi\u00d6n ph\u00d0p chia nh\u00f0 chia cho s\u00e8 t\u00f9 nhi\u00aan. 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : a) 19,72 : 5,8 ; b) 8,216 : 5,2 ; c) 12,88 : 0,25 ; d) 17,4 : 1,45. 2 Bi\u00d5t 4,5l d\u00c7u c\u00a9n n\u00c6ng 3,42kg. H\u00e1i 8l d\u00c7u c\u00a9n n\u00c6ng bao nhi\u00aau ki-l\u00ab-gam ? 3 May m\u00e7i b\u00e9 qu\u00c7n \u00b8o h\u00d5t 2,8m v\u00b6i. H\u00e1i c\u00e3 429,5m v\u00b6i th\u00d7 may \u00ae\u00f0\u00eec nhi\u00d2u nh\u00cat bao nhi\u00aau b\u00e9 qu\u00c7n \u00b8o nh\u00f0 th\u00d5 v\u00b5 c\u00dfn th\u00f5a m\u00cay m\u00d0t v\u00b6i ? 71","CM YK Tr.72 Luy\u00d6n t\u00cbp 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : c) 0,3068 : 0,26 ; d) 98,156 : 4,63. a) 17,55 : 3,9 ; b) 0,603 : 0,09 ; 2 T\u00d7m x : a) x \u00d7 1,8 = 72 ; b) x \u00d7 0,34 = 1,19 \u00d7 1,02 ; c) x \u00d7 1,36 = 4,76 \u00d7 4,08. 3 Bi\u00d5t 5,2l d\u00c7u c\u00a9n n\u00c6ng 3,952kg. H\u00e1i c\u00e3 bao nhi\u00aau l\u00ddt d\u00c7u n\u00d5u ch\u00f3ng c\u00a9n n\u00c6ng 5,32kg ? 4 T\u00d7m s\u00e8 d\u00f0 c\u00f1a ph\u00d0p chia 218 : 3,7 n\u00d5u ch\u00d8 l\u00cay \u00ae\u00d5n hai ch\u00f7 s\u00e8 \u00eb ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a th\u00f0\u00acng. Luy\u00d6n t\u00cbp chung b) 30 + 0,5 + 0,04 ; 1 T\u00ddnh : a) 400 + 50 + 0,07 ; c) 100 + 7 + ; d) 35 + . 2 > ? ... 4,35 ... 2,2 < 14,09 ... ... 7,15 = 3 T\u00d7m s\u00e8 d\u00f0 c\u00f1a ph\u00d0p chia, n\u00d5u ch\u00d8 l\u00cay \u00ae\u00d5n hai ch\u00f7 s\u00e8 \u00eb ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a th\u00f0\u00acng : a) 6,251 : 7 ; b) 33,14 : 58 ; c) 375,23 : 69. 4 T\u00d7m x : b) 210 : x = 14,92 \u2212 6,52 ; a) 0,8 \u00d7 x = 1,2 \u00d7 10 ; d) 6,2 \u00d7 x = 43,18 + 18,82. c) 25 : x = 16 : 10 ; 72","CM YK Tr.73 Luy\u00d6n t\u00cbp chung 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : b) 483 : 35 ; a) 266,22 : 34 ; d) 3 : 6,25. c) 91,08 : 3,6 ; 2 T\u00ddnh : b) 8,64 : (1,46 + 3,34) + 6,32. a) (128,4 \u2212 73,2) : 2,4 \u2212 18,32 ; 3 M\u00e9t \u00ae\u00e9ng c\u00ac m\u00e7i gi\u00ea ch\u00b9y h\u00d5t 0,5l d\u00c7u. H\u00e1i c\u00e3 120l d\u00c7u th\u00d7 \u00ae\u00e9ng c\u00ac \u00ae\u00e3 ch\u00b9y \u00ae\u00f0\u00eec trong bao nhi\u00aau gi\u00ea ? 4 T\u00d7m x : b) x + 18,7 = 50,5 : 2,5 ; a) x \u2212 1,27 = 13,5 : 4,5 ; c) x \u00d7 12,5 = 6 \u00d7 2,5. T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m a) V\u00dd d\u00f4 1 : Di\u00d6n t\u00ddch m\u00e9t v\u00f0\u00ean hoa l\u00b5 100m2, trong \u00ae\u00e3 c\u00e3 25m2 tr\u00e5ng hoa h\u00e5ng. T\u00d7m t\u00d8 s\u00e8 c\u00f1a di\u00d6n t\u00ddch tr\u00e5ng hoa h\u00e5ng v\u00b5 di\u00d6n t\u00ddch v\u00f0\u00ean hoa. 10m T\u00d8 s\u00e8 c\u00f1a di\u00d6n t\u00ddch tr\u00e5ng hoa h\u00e5ng v\u00b5 di\u00d6n t\u00ddch v\u00f0\u00ean hoa l\u00b5 25 : 100 25m2 hay . Ta vi\u00d5t : = 25% ; \u00ae\u00e4c l\u00b5 : hai m\u00f0\u00aci l\u00a8m ph\u00c7n tr\u00a8m. Ta n\u00e3i : T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a di\u00d6n t\u00ddch tr\u00e5ng hoa h\u00e5ng v\u00b5 di\u00d6n t\u00ddch v\u00f0\u00ean hoa l\u00b5 25% ; ho\u00c6c : Di\u00d6n t\u00ddch tr\u00e5ng hoa h\u00e5ng chi\u00d5m 25% di\u00d6n t\u00ddch v\u00f0\u00ean hoa. 73","CM YK Tr.74 b) V\u00dd d\u00f4 2 : M\u00e9t tr\u00f0\u00eang c\u00e3 400 h\u00e4c sinh, trong \u00ae\u00e3 c\u00e3 80 h\u00e4c sinh gi\u00e1i. T\u00d7m t\u00d8 s\u00e8 c\u00f1a s\u00e8 h\u00e4c sinh gi\u00e1i v\u00b5 s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang. T\u00d8 s\u00e8 c\u00f1a s\u00e8 h\u00e4c sinh gi\u00e1i v\u00b5 s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 : 80 : 400 hay . Ta c\u00e3 : 80 : 400 = = = 20%. Ta c\u00f2ng n\u00e3i r\u00bbng : T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 h\u00e4c sinh gi\u00e1i v\u00b5 s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 20% ; ho\u00c6c : S\u00e8 h\u00e4c sinh gi\u00e1i chi\u00d5m 20% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang. T\u00d8 s\u00e8 n\u00b5y cho bi\u00d5t c\u00f8 100 h\u00e4c sinh c\u00f1a tr\u00f0\u00eang th\u00d7 c\u00e3 20 h\u00e4c sinh gi\u00e1i. 1 Vi\u00d5t (theo m\u00c9u) : . M\u00c9u : 2 Ki\u00d3m tra s\u00b6n ph\u00c8m c\u00f1a m\u00e9t nh\u00b5 m\u00b8y, ng\u00f0\u00eai ta th\u00cay trung b\u00d7nh c\u00f8 100 s\u00b6n ph\u00c8m th\u00d7 c\u00e3 95 s\u00b6n ph\u00c8m \u00ae\u00b9t chu\u00c8n. H\u00e1i s\u00e8 s\u00b6n ph\u00c8m \u00ae\u00b9t chu\u00c8n chi\u00d5m bao nhi\u00aau ph\u00c7n tr\u00a8m t\u00e6ng s\u00e8 s\u00b6n ph\u00c8m c\u00f1a nh\u00b5 m\u00b8y ? 3 M\u00e9t v\u00f0\u00ean c\u00a9y c\u00e3 1000 c\u00a9y, trong \u00ae\u00e3 c\u00e3 540 c\u00a9y l\u00cay g\u00e7 v\u00b5 c\u00dfn l\u00b9i l\u00b5 c\u00a9y \u00a8n qu\u00b6. a) S\u00e8 c\u00a9y l\u00cay g\u00e7 chi\u00d5m bao nhi\u00aau ph\u00c7n tr\u00a8m s\u00e8 c\u00a9y trong v\u00f0\u00ean ? b) T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 c\u00a9y \u00a8n qu\u00b6 v\u00b5 s\u00e8 c\u00a9y trong v\u00f0\u00ean l\u00b5 bao nhi\u00aau ? 74","CM YK Tr.75 Gi\u00b6i to\u00b8n v\u00d2 t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m a) V\u00dd d\u00f4 : Tr\u00f0\u00eang Ti\u00d3u h\u00e4c V\u00b9n Th\u00e4 c\u00e3 600 h\u00e4c sinh, trong \u00ae\u00e3 c\u00e3 315 h\u00e4c sinh n\u00f7. T\u00d7m t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 h\u00e4c sinh n\u00f7 v\u00b5 s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang. T\u00d8 s\u00e8 c\u00f1a s\u00e8 h\u00e4c sinh n\u00f7 v\u00b5 s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 315 : 600. Ta c\u00e3 : 315 : 600 = 0,525 0,525 \u00d7 100 : 100 = 52,5 : 100 = 52,5%. V\u00cby t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 h\u00e4c sinh n\u00f7 v\u00b5 s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 52,5%. Th\u00abng th\u00f0\u00eang ta vi\u00d5t g\u00e4n c\u00b8ch t\u00ddnh nh\u00f0 sau : 315 : 600 = 0,525 = 52,5%. Mu\u00e8n t\u00d7m t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a hai s\u00e8 315 v\u00b5 600 ta l\u00b5m nh\u00f0 sau : \u2212 T\u00d7m th\u00f0\u00acng c\u00f1a 315 v\u00b5 600. \u2212 Nh\u00a9n th\u00f0\u00acng \u00ae\u00e3 v\u00edi 100 v\u00b5 vi\u00d5t th\u00aam k\u00dd hi\u00d6u % v\u00b5o b\u00aan ph\u00b6i t\u00ddch t\u00d7m \u00ae\u00f0\u00eec. b) B\u00b5i to\u00b8n : Trong 80kg n\u00f0\u00edc bi\u00d3n c\u00e3 2,8kg mu\u00e8i. T\u00d7m t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a l\u00f0\u00eeng mu\u00e8i trong n\u00f0\u00edc bi\u00d3n. B\u00b5i gi\u00b6i T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a l\u00f0\u00eeng mu\u00e8i trong n\u00f0\u00edc bi\u00d3n l\u00b5 : 2,8 : 80 = 0,035 0,035 = 3,5%. \u00a7\u00b8p s\u00e8 : 3,5%. 1 Vi\u00d5t th\u00b5nh t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m (theo m\u00c9u) : 0,57 ; 0,3 ; 0,234 ; 1,35. M\u00c9u : 0,57 = 57%. 2 T\u00ddnh t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a hai s\u00e8 (theo m\u00c9u) : a) 19 v\u00b5 30 ; b) 45 v\u00b5 61 ; c) 1,2 v\u00b5 26. M\u00c9u : a) 19 : 30 = 0,6333 ... = 63,33%. Ch\u00f3 \u00fd : N\u00d5u ph\u00c7n th\u00cbp ph\u00a9n c\u00f1a th\u00f0\u00acng c\u00e3 nhi\u00d2u ch\u00f7 s\u00e8 th\u00d7 ch\u00d8 l\u00cay \u00ae\u00d5n 4 ch\u00f7 s\u00e8. 3 M\u00e9t l\u00edp h\u00e4c c\u00e3 25 h\u00e4c sinh, trong \u00ae\u00e3 c\u00e3 13 h\u00e4c sinh n\u00f7. H\u00e1i s\u00e8 h\u00e4c sinh n\u00f7 chi\u00d5m bao nhi\u00aau ph\u00c7n tr\u00a8m s\u00e8 h\u00e4c sinh c\u00f1a l\u00edp h\u00e4c \u00ae\u00e3 ? 75","CM YK Tr.76 Luy\u00d6n t\u00cbp 1 T\u00ddnh (theo m\u00c9u) : c) 14,2% \u00d7 4 ; d) 216% : 8. a) 27,5% + 38% ; b) 30% \u2212 16% ; 112,5% \u2212 13% = 99,5% M\u00c9u : 6% + 15% = 21% 60% : 5 = 12% 14,2% \u00d7 3 = 42,6% 2 Theo k\u00d5 ho\u00b9ch, n\u00a8m v\u00f5a qua th\u00abn Ho\u00b5 An ph\u00b6i tr\u00e5ng 20ha ng\u00ab. \u00a7\u00d5n h\u00d5t th\u00b8ng 9 th\u00abn Ho\u00b5 An tr\u00e5ng \u00ae\u00f0\u00eec 18ha v\u00b5 h\u00d5t n\u00a8m tr\u00e5ng \u00ae\u00f0\u00eec 23,5ha ng\u00ab. H\u00e1i : a) \u00a7\u00d5n h\u00d5t th\u00b8ng 9 th\u00abn Ho\u00b5 An \u00ae\u00b7 th\u00f9c hi\u00d6n \u00ae\u00f0\u00eec bao nhi\u00aau ph\u00c7n tr\u00a8m k\u00d5 ho\u00b9ch c\u00b6 n\u00a8m ? b) H\u00d5t n\u00a8m th\u00abn Ho\u00b5 An \u00ae\u00b7 th\u00f9c hi\u00d6n \u00ae\u00f0\u00eec bao nhi\u00aau ph\u00c7n tr\u00a8m v\u00b5 v\u00f0\u00eet m\u00f8c k\u00d5 ho\u00b9ch c\u00b6 n\u00a8m bao nhi\u00aau ph\u00c7n tr\u00a8m ? 3 M\u00e9t ng\u00f0\u00eai b\u00e1 ra 42 000 \u00ae\u00e5ng ti\u00d2n v\u00e8n mua rau. Sau khi b\u00b8n h\u00d5t s\u00e8 rau, ng\u00f0\u00eai \u00ae\u00e3 thu \u00ae\u00f0\u00eec 52 500 \u00ae\u00e5ng. H\u00e1i : a) Ti\u00d2n b\u00b8n rau b\u00bbng bao nhi\u00aau ph\u00c7n tr\u00a8m ti\u00d2n v\u00e8n ? b) Ng\u00f0\u00eai \u00ae\u00e3 \u00ae\u00b7 l\u00b7i bao nhi\u00aau ph\u00c7n tr\u00a8m ? Gi\u00b6i to\u00b8n v\u00d2 t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m (ti\u00d5p theo) a) V\u00dd d\u00f4 : M\u00e9t tr\u00f0\u00eang ti\u00d3u h\u00e4c c\u00e3 800 h\u00e4c sinh, trong \u00ae\u00e3 s\u00e8 h\u00e4c sinh n\u00f7 chi\u00d5m 52,5%. T\u00ddnh s\u00e8 h\u00e4c sinh n\u00f7 c\u00f1a tr\u00f0\u00eang \u00ae\u00e3. C\u00e3 th\u00d3 hi\u00d3u 100% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 t\u00cat c\u00b6 s\u00e8 h\u00e4c sinh c\u00f1a tr\u00f0\u00eang, \u00eb \u00ae\u00a9y 100% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 800 em. Ta c\u00e3 : 1% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 : 800 : 100 = 8 (h\u00e4c sinh) S\u00e8 h\u00e4c sinh n\u00f7 hay 52,5% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 : 8 \u00d7 52,5 = 420 (h\u00e4c sinh) Hai b\u00f0\u00edc t\u00ddnh tr\u00aan c\u00e3 th\u00d3 vi\u00d5t g\u00e9p th\u00b5nh : 800 : 100 \u00d7 52,5 = 420 ho\u00c6c 800 \u00d7 52,5 : 100 = 420 Mu\u00e8n t\u00d7m 52,5% c\u00f1a 800 ta c\u00e3 th\u00d3 l\u00cay 800 chia cho 100 r\u00e5i nh\u00a9n v\u00edi 52,5 ho\u00c6c l\u00cay 800 nh\u00a9n v\u00edi 52,5 r\u00e5i chia cho 100. 76","CM YK Tr.77 b) B\u00b5i to\u00b8n : L\u00b7i su\u00cat ti\u00d5t ki\u00d6m l\u00b5 0,5% m\u00e9t th\u00b8ng. M\u00e9t ng\u00f0\u00eai g\u00f6i ti\u00d5t ki\u00d6m 1 000 000 \u00ae\u00e5ng. T\u00ddnh s\u00e8 ti\u00d2n l\u00b7i sau m\u00e9t th\u00b8ng. B\u00b5i gi\u00b6i S\u00e8 ti\u00d2n l\u00b7i sau m\u00e9t th\u00b8ng l\u00b5 : 1000000 : 100 \u00d7 0,5 = 5000 (\u00ae\u00e5ng) \u00a7\u00b8p s\u00e8 : 5000 \u00ae\u00e5ng. 1 M\u00e9t l\u00edp h\u00e4c c\u00e3 32 h\u00e4c sinh, trong \u00ae\u00e3 s\u00e8 h\u00e4c sinh 10 tu\u00e6i chi\u00d5m 75%, c\u00dfn l\u00b9i l\u00b5 h\u00e4c sinh 11 tu\u00e6i. T\u00ddnh s\u00e8 h\u00e4c sinh 11 tu\u00e6i c\u00f1a l\u00edp h\u00e4c \u00ae\u00e3. 2 L\u00b7i su\u00cat ti\u00d5t ki\u00d6m l\u00b5 0,5% m\u00e9t th\u00b8ng. M\u00e9t ng\u00f0\u00eai g\u00f6i ti\u00d5t ki\u00d6m 5 000 000 \u00ae\u00e5ng. H\u00e1i sau m\u00e9t th\u00b8ng c\u00b6 s\u00e8 ti\u00d2n g\u00f6i v\u00b5 s\u00e8 ti\u00d2n l\u00b7i l\u00b5 bao nhi\u00aau ? 3 M\u00e9t x\u00f0\u00ebng may \u00ae\u00b7 d\u00efng h\u00d5t 345m v\u00b6i \u00ae\u00d3 may qu\u00c7n \u00b8o, trong \u00ae\u00e3 s\u00e8 v\u00b6i may qu\u00c7n chi\u00d5m 40%. H\u00e1i s\u00e8 v\u00b6i may \u00b8o l\u00b5 bao nhi\u00aau m\u00d0t ? luy\u00d6n t\u00cbp 1 a) T\u00d7m 15% c\u00f1a 320kg ; b) T\u00d7m 24% c\u00f1a 235m2 ; c) T\u00d7m 0,4% c\u00f1a 350. 2 M\u00e9t ng\u00f0\u00eai b\u00b8n 120kg g\u00b9o, trong \u00ae\u00e3 c\u00e3 35% l\u00b5 g\u00b9o n\u00d5p. H\u00e1i ng\u00f0\u00eai \u00ae\u00e3 b\u00b8n \u00ae\u00f0\u00eec bao nhi\u00aau ki-l\u00ab-gam g\u00b9o n\u00d5p ? 3 M\u00e9t m\u00b6nh \u00ae\u00cat h\u00d7nh ch\u00f7 nh\u00cbt c\u00e3 chi\u00d2u d\u00b5i 18m v\u00b5 chi\u00d2u r\u00e9ng 15m. Ng\u00f0\u00eai ta d\u00b5nh 20% di\u00d6n t\u00ddch m\u00b6nh \u00ae\u00cat \u00ae\u00d3 l\u00b5m nh\u00b5. T\u00ddnh di\u00d6n t\u00ddch ph\u00c7n \u00ae\u00cat l\u00b5m nh\u00b5. 4 M\u00e9t v\u00f0\u00ean c\u00a9y \u00a8n qu\u00b6 c\u00e3 1200 c\u00a9y. H\u00b7y t\u00ddnh nh\u00c8m 5%, 10%, 20%, 25% s\u00e8 c\u00a9y trong v\u00f0\u00ean. 77","CM YK Tr.78 Gi\u00b6i to\u00b8n v\u00d2 t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m (ti\u00d5p theo) a) V\u00dd d\u00f4 : S\u00e8 h\u00e4c sinh n\u00f7 c\u00f1a m\u00e9t tr\u00f0\u00eang l\u00b5 420 em v\u00b5 chi\u00d5m 52,5% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang. H\u00e1i tr\u00f0\u00eang \u00ae\u00e3 c\u00e3 bao nhi\u00aau h\u00e4c sinh ? 52,5% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 420 em. 1% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 : 420 : 52,5 = 8 (h\u00e4c sinh) S\u00e8 h\u00e4c sinh c\u00f1a tr\u00f0\u00eang hay 100% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang l\u00b5 : 8 \u00d7 100 = 800 (h\u00e4c sinh) Hai b\u00f0\u00edc t\u00ddnh tr\u00aan c\u00e3 th\u00d3 vi\u00d5t g\u00e9p th\u00b5nh : 420 : 52,5 \u00d7 100 = 800 ho\u00c6c 420 \u00d7 100 : 52,5 = 800 Mu\u00e8n t\u00d7m m\u00e9t s\u00e8 bi\u00d5t 52,5% c\u00f1a n\u00e3 l\u00b5 420, ta c\u00e3 th\u00d3 l\u00cay 420 chia cho 52,5 r\u00e5i nh\u00a9n v\u00edi 100 ho\u00c6c l\u00cay 420 nh\u00a9n v\u00edi 100 r\u00e5i chia cho 52,5. b) B\u00b5i to\u00b8n : N\u00a8m v\u00f5a qua m\u00e9t nh\u00b5 m\u00b8y ch\u00d5 t\u00b9o \u00ae\u00f0\u00eec 1590 \u00ab t\u00ab. T\u00ddnh ra nh\u00b5 m\u00b8y \u00ae\u00b7 \u00ae\u00b9t 120% k\u00d5 ho\u00b9ch. H\u00e1i theo k\u00d5 ho\u00b9ch, nh\u00b5 m\u00b8y d\u00f9 \u00ae\u00denh s\u00b6n xu\u00cat bao nhi\u00aau \u00ab t\u00ab ? B\u00b5i gi\u00b6i S\u00e8 \u00ab t\u00ab nh\u00b5 m\u00b8y d\u00f9 \u00ae\u00denh s\u00b6n xu\u00cat l\u00b5 : 1590 \u00d7 100 : 120 = 1325 (\u00ab t\u00ab) \u00a7\u00b8p s\u00e8 : 1325 \u00ab t\u00ab. 1 S\u00e8 h\u00e4c sinh kh\u00b8 gi\u00e1i c\u00f1a Tr\u00f0\u00eang V\u00b9n Th\u00denh l\u00b5 552 em, chi\u00d5m 92% s\u00e8 h\u00e4c sinh to\u00b5n tr\u00f0\u00eang. H\u00e1i Tr\u00f0\u00eang V\u00b9n Th\u00denh c\u00e3 bao nhi\u00aau h\u00e4c sinh ? 2 Ki\u00d3m tra s\u00b6n ph\u00c8m c\u00f1a m\u00e9t x\u00f0\u00ebng may, ng\u00f0\u00eai ta th\u00cay c\u00e3 732 s\u00b6n ph\u00c8m \u00ae\u00b9t chu\u00c8n, chi\u00d5m 91,5% t\u00e6ng s\u00e8 s\u00b6n ph\u00c8m. T\u00ddnh t\u00e6ng s\u00e8 s\u00b6n ph\u00c8m. 3 M\u00e9t kho g\u00b9o ch\u00f8a g\u00b9o t\u00ce v\u00b5 g\u00b9o n\u00d5p, trong \u00ae\u00e3 c\u00e3 5 t\u00can g\u00b9o n\u00d5p. T\u00ddnh nh\u00c8m t\u00e6ng s\u00e8 g\u00b9o c\u00f1a kho, n\u00d5u s\u00e8 g\u00b9o n\u00d5p chi\u00d5m : a) 10% s\u00e8 g\u00b9o trong kho ; b) 25% s\u00e8 g\u00b9o trong kho. 78","CM YK Tr.79 Luy\u00d6n t\u00cbp 1 a) T\u00ddnh t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a hai s\u00e8 37 v\u00b5 42. b) M\u00e9t t\u00e6 s\u00b6n xu\u00cat l\u00b5m \u00ae\u00f0\u00eec 1200 s\u00b6n ph\u00c8m, trong \u00ae\u00e3 anh Ba l\u00b5m \u00ae\u00f0\u00eec 126 s\u00b6n ph\u00c8m. H\u00e1i anh Ba l\u00b5m \u00ae\u00f0\u00eec bao nhi\u00aau ph\u00c7n tr\u00a8m s\u00e8 s\u00b6n ph\u00c8m c\u00f1a t\u00e6 ? 2 a) T\u00d7m 30% c\u00f1a 97. b) M\u00e9t c\u00f6a h\u00b5ng b\u00e1 ra 6 000 000 \u00ae\u00e5ng ti\u00d2n v\u00e8n. Bi\u00d5t c\u00f6a h\u00b5ng \u00ae\u00e3 \u00ae\u00b7 l\u00b7i 15%, t\u00ddnh s\u00e8 ti\u00d2n l\u00b7i. 3 a) T\u00d7m m\u00e9t s\u00e8 bi\u00d5t 30% c\u00f1a n\u00e3 l\u00b5 72. b) M\u00e9t c\u00f6a h\u00b5ng \u00ae\u00b7 b\u00b8n \u00ae\u00f0\u00eec 420kg g\u00b9o v\u00b5 s\u00e8 g\u00b9o \u00ae\u00e3 b\u00bbng 10,5% t\u00e6ng s\u00e8 g\u00b9o c\u00f1a c\u00f6a h\u00b5ng tr\u00f0\u00edc khi b\u00b8n. H\u00e1i tr\u00f0\u00edc khi b\u00b8n c\u00f6a h\u00b5ng \u00ae\u00e3 c\u00e3 bao nhi\u00aau t\u00can g\u00b9o ? Luy\u00d6n t\u00cbp chung 1 T\u00ddnh : b) 1 : 12,5 ; c) 109,98 : 42,3. a) 216,72 : 42 ; 2 T\u00ddnh : b) 8,16 : (1,32 + 3,48) \u2212 0,345 : 2. a) (131,4 \u2212 80,8) : 2,3 + 21,84 \u00d7 2 ; 3 Cu\u00e8i n\u00a8m 2000 s\u00e8 d\u00a9n c\u00f1a m\u00e9t ph\u00f0\u00eang l\u00b5 15 625 ng\u00f0\u00eai. Cu\u00e8i n\u00a8m 2001 s\u00e8 d\u00a9n c\u00f1a ph\u00f0\u00eang \u00ae\u00e3 l\u00b5 15 875 ng\u00f0\u00eai. a) H\u00e1i t\u00f5 cu\u00e8i n\u00a8m 2000 \u00ae\u00d5n cu\u00e8i n\u00a8m 2001 s\u00e8 d\u00a9n c\u00f1a ph\u00f0\u00eang \u00ae\u00e3 t\u00a8ng th\u00aam bao nhi\u00aau ph\u00c7n tr\u00a8m ? b) N\u00d5u t\u00f5 cu\u00e8i n\u00a8m 2001 \u00ae\u00d5n cu\u00e8i n\u00a8m 2002 s\u00e8 d\u00a9n c\u00f1a ph\u00f0\u00eang \u00ae\u00e3 c\u00f2ng t\u00a8ng th\u00aam b\u00cay nhi\u00aau ph\u00c7n tr\u00a8m th\u00d7 cu\u00e8i n\u00a8m 2002 s\u00e8 d\u00a9n c\u00f1a ph\u00f0\u00eang \u00ae\u00e3 l\u00b5 bao nhi\u00aau ng\u00f0\u00eai ? 79","CM YK Tr.80 4 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : M\u00e9t ng\u00f0\u00eai b\u00b8n h\u00b5ng b\u00de l\u00e7 70 000 \u00ae\u00e5ng v\u00b5 s\u00e8 ti\u00d2n \u00ae\u00e3 b\u00bbng 7% s\u00e8 ti\u00d2n v\u00e8n b\u00e1 ra. \u00a7\u00d3 t\u00ddnh s\u00e8 ti\u00d2n v\u00e8n c\u00f1a ng\u00f0\u00eai \u00ae\u00e3, ta c\u00c7n t\u00ddnh : A. 70000 : 7 B. 70000 \u00d7 7 : 100 C. 70000 \u00d7 100 : 7 D. 70000 \u00d7 7 luy\u00d6n t\u00cbp chung 1 Vi\u00d5t c\u00b8c h\u00e7n s\u00e8 sau th\u00b5nh s\u00e8 th\u00cbp ph\u00a9n : . 2 T\u00d7m x : a) x \u00d7 100 = 1,643 + 7,357 ; b) 0,16 : x = 2 \u2212 0,4. 3 M\u00e9t m\u00b8y b\u00acm trong ba ng\u00b5y h\u00f3t h\u00d5t n\u00f0\u00edc \u00eb h\u00e5. Ng\u00b5y th\u00f8 nh\u00cat m\u00b8y b\u00acm \u00ae\u00e3 h\u00f3t \u00ae\u00f0\u00eec 35% l\u00f0\u00eeng n\u00f0\u00edc trong h\u00e5, ng\u00b5y th\u00f8 hai h\u00f3t \u00ae\u00f0\u00eec 40% l\u00f0\u00eeng n\u00f0\u00edc trong h\u00e5. H\u00e1i ng\u00b5y th\u00f8 ba m\u00b8y b\u00acm \u00ae\u00e3 h\u00f3t \u00ae\u00f0\u00eec bao nhi\u00aau ph\u00c7n tr\u00a8m l\u00f0\u00eeng n\u00f0\u00edc trong h\u00e5 ? 4 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc k\u00d5t qu\u00b6 \u00ae\u00f3ng : 805m2 = ... ha. S\u00e8 th\u00ddch h\u00eep \u00ae\u00d3 vi\u00d5t v\u00b5o ch\u00e7 ch\u00cam l\u00b5 : A. 80,5 B. 8,05 C. 0,805 D. 0,0805 80","CM YK Tr.81 Gi\u00edi thi\u00d6u m\u00b8y t\u00ddnh b\u00e1 t\u00f3i a) M\u00ab t\u00b6 m\u00b8y t\u00ddnh b\u00e1 t\u00f3i 0 123456 78 M M\u00b8y t\u00ddnh b\u00e1 t\u00f3i gi\u00f3p ta th\u00f9c hi\u00d6n c\u00b8c ph\u00d0p t\u00ddnh ON\/C R-CM M+ M\u2212 OFF th\u00f0\u00eang d\u00efng nh\u00f0 c\u00e9ng, tr\u00f5, nh\u00a9n, chia v\u00b5 gi\u00b6i to\u00b8n v\u00d2 t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m. 789 C\u00e3 nhi\u00d2u lo\u00b9i m\u00b8y t\u00ddnh b\u00e1 t\u00f3i. V\u00d2 c\u00ac b\u00b6n c\u00b8c lo\u00b9i %4 5 6\u00d7 m\u00b8y t\u00ddnh b\u00e1 t\u00f3i v\u00b5 c\u00b8ch s\u00f6 d\u00f4ng ch\u00f3ng t\u00f0\u00acng t\u00f9 \u221a 123\u2212 nh\u00f0 nhau. V\u00dd d\u00f4, m\u00e9t m\u00b8y t\u00ddnh c\u00e3 b\u00d2 m\u00c6t nh\u00f0 CE 0 . = + h\u00d7nh b\u00aan : Ngo\u00b5i m\u00b5n h\u00d7nh, ta th\u00cay c\u00e3 c\u00b8c ph\u00ddm sau : \u2212 Ph\u00ddm ON\/C \u00ae\u00d3 b\u00cbt m\u00b8y. \u2212 Ph\u00ddm OFF \u00ae\u00d3 t\u00bet m\u00b8y. \u2212 C\u00b8c ph\u00ddm s\u00e8 t\u00f5 0 \u00ae\u00d5n 9 \u00ae\u00d3 nh\u00cbp s\u00e8. \u2212 C\u00b8c ph\u00ddm ph\u00d0p t\u00ddnh c\u00e9ng, tr\u00f5, nh\u00a9n, chia : + , \u2212 , \u00d7 , \u2212 Ph\u00ddm \u00ae\u00d3 ghi d\u00cau ph\u00c8y trong c\u00b8c s\u00e8 th\u00cbp ph\u00a9n. \u2212 Ph\u00ddm = \u00ae\u00d3 hi\u00d6n k\u00d5t qu\u00b6 ph\u00d0p t\u00ddnh tr\u00aan m\u00b5n h\u00d7nh. \u2212 Ph\u00ddm CE \u00ae\u00d3 xo\u00b8 s\u00e8 v\u00f5a nh\u00cbp v\u00b5o n\u00d5u nh\u00cbp sai. \u2212 C\u00b8c ph\u00ddm \u00ae\u00c6c bi\u00d6t kh\u00b8c : R-CM , M\u2212 , M+ , \u221a , % , b) Th\u00f9c hi\u00d6n c\u00b8c ph\u00d0p t\u00ddnh b\u00bbng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i = \u2212 \u00a7\u00d3 m\u00b8y ho\u00b9t \u00ae\u00e9ng, c\u00c7n \u00can ph\u00ddm ON\/C (b\u00cbt m\u00b8y). \u2212 \u00a7\u00d3 t\u00ddnh 25,3 + 7,09 ta l\u00c7n l\u00f0\u00eet \u00can c\u00b8c ph\u00ddm sau : 25 . 3+7 . 09 \u2212 Tr\u00aan m\u00b5n h\u00d7nh xu\u00cat hi\u00d6n k\u00d5t qu\u00b6 32.39, t\u00f8c l\u00b5 32,39. \u00a7\u00d3 th\u00f9c hi\u00d6n c\u00b8c ph\u00d0p t\u00ddnh tr\u00f5, nh\u00a9n, chia ta l\u00b5m t\u00f0\u00acng t\u00f9. 81","CM YK Tr.82 1 Th\u00f9c hi\u00d6n c\u00b8c ph\u00d0p t\u00ddnh sau r\u00e5i ki\u00d3m tra l\u00b9i k\u00d5t qu\u00b6 b\u00bbng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i : a) 126,45 + 796,892 ; b) 352,19 \u2212 189,471 ; c) 75,54 \u00d7 39 ; d) 308,85 : 14,5. 2 Vi\u00d5t c\u00b8c ph\u00a9n s\u00e8 sau th\u00b5nh s\u00e8 th\u00cbp ph\u00a9n (d\u00efng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i \u00ae\u00d3 t\u00ddnh) : . 3 M\u00e9t h\u00e4c sinh l\u00c7n l\u00f0\u00eet \u00can c\u00b8c ph\u00ddm sau : 4 . 5\u00d76\u22127= Theo em, b\u00b9n \u00ae\u00e3 \u00ae\u00b7 t\u00ddnh gi\u00b8 tr\u00de c\u00f1a bi\u00d3u th\u00f8c n\u00b5o ? s\u00f6 d\u00f4ng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i \u00ae\u00d3 gi\u00b6i to\u00b8n v\u00d2 t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m a) V\u00dd d\u00f4 1 : T\u00ddnh t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a 7 v\u00b5 40. \u2212 L\u00c7n l\u00f0\u00eet \u00can c\u00b8c ph\u00ddm : 7 40= \u2212 Tr\u00aan m\u00b5n h\u00d7nh xu\u00cat hi\u00d6n k\u00d5t qu\u00b6 0.175. \u2212 M\u00b8y \u00ae\u00b7 t\u00ddnh : 7 : 40 = 0,175. V\u00cby : 7 : 40 = 0,175 = 17,5%. Ch\u00f3 \u00fd : C\u00e3 th\u00d3 l\u00c7n l\u00f0\u00eet \u00can c\u00b8c ph\u00ddm : 7 4 0% Khi \u00ae\u00e3 tr\u00aan m\u00b5n h\u00d7nh xu\u00cat hi\u00d6n s\u00e8 17.5 th\u00d7 \u00ae\u00a9y l\u00b5 k\u00d5t qu\u00b6 17,5%. 82","CM YK Tr.83 b) V\u00dd d\u00f4 2 : T\u00ddnh 34% c\u00f1a 56. \u2212 L\u00c7n l\u00f0\u00eet \u00can c\u00b8c ph\u00ddm : 5 6 \u00d7 3 4% \u2212 Tr\u00aan m\u00b5n h\u00d7nh xu\u00cat hi\u00d6n k\u00d5t qu\u00b6 19.04. \u2212 M\u00b8y \u00ae\u00b7 t\u00ddnh : 56 \u00d7 34% = 56 \u00d7 34 : 100 = 19,04. V\u00cby : 34% c\u00f1a 56 l\u00b5 19,04. c) V\u00dd d\u00f4 3 : T\u00d7m m\u00e9t s\u00e8 bi\u00d5t 65% c\u00f1a n\u00e3 b\u00bbng 78. \u2212 L\u00c7n l\u00f0\u00eet \u00can c\u00b8c ph\u00ddm : 7 8 6 5% \u2212 Tr\u00aan m\u00b5n h\u00d7nh xu\u00cat hi\u00d6n k\u00d5t qu\u00b6 120. \u2212 M\u00b8y \u00ae\u00b7 t\u00ddnh : 78 : 65% = 78 : 65 \u00d7 100 = 120. V\u00cby : S\u00e8 c\u00c7n t\u00d7m l\u00b5 120. 1 Trong b\u00b6ng sau, c\u00e9t cu\u00e8i c\u00efng ghi t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 h\u00e4c sinh n\u00f7 v\u00b5 t\u00e6ng s\u00e8 h\u00e4c sinh c\u00f1a m\u00e9t s\u00e8 tr\u00f0\u00eang. H\u00b7y d\u00efng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i \u00ae\u00d3 t\u00ddnh v\u00b5 vi\u00d5t k\u00d5t qu\u00b6 v\u00b5o c\u00e9t \u00ae\u00e3. T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 Tr\u00f0\u00eang S\u00e8 h\u00e4c sinh S\u00e8 h\u00e4c sinh n\u00f7 h\u00e4c sinh n\u00f7 v\u00b5 An H\u00b5 612 t\u00e6ng s\u00e8 h\u00e4c sinh An H\u00b6i 578 An D\u00f0\u00acng 714 311 An S\u00acn 807 294 356 400 83","CM YK Tr.84 2 Trung b\u00d7nh xay x\u00b8t 1 t\u00b9 th\u00e3c th\u00d7 thu \u00ae\u00f0\u00eec 69kg g\u00b9o, t\u00f8c l\u00b5 t\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a g\u00b9o v\u00b5 th\u00e3c l\u00b5 69%. B\u00bbng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i, h\u00b7y t\u00ddnh s\u00e8 g\u00b9o thu \u00ae\u00f0\u00eec khi xay x\u00b8t th\u00e3c v\u00b5 vi\u00d5t v\u00b5o \u00ab tr\u00e8ng (theo m\u00c9u) : Th\u00e3c (kg) G\u00b9o (kg) 100 69 150 125 110 88 3 V\u00edi l\u00b7i su\u00cat ti\u00d5t ki\u00d6m 0,6% m\u00e9t th\u00b8ng, c\u00c7n g\u00f6i bao nhi\u00aau ti\u00d2n \u00ae\u00d3 sau m\u00e9t th\u00b8ng nh\u00cbn \u00ae\u00f0\u00eec s\u00e8 ti\u00d2n l\u00b7i l\u00b5 : a) 30 000 \u00ae\u00e5ng ; b) 60 000 \u00ae\u00e5ng ; c) 90 000 \u00ae\u00e5ng. (D\u00efng m\u00b8y t\u00ddnh b\u00e1 t\u00f3i \u00ae\u00d3 t\u00ddnh) 84","Ch\u00f0\u00acng ba H\u00d7nh h\u00e4c H\u00d7nh tam gi\u00b8c H\u00d7nh tam gi\u00b8c ABC c\u00e3 : a) H\u00d7nh tam gi\u00b8c G Ba c\u00b9nh l\u00b5 : c\u00b9nh AB, c\u00b9nh AC, c\u00b9nh BC. A G Ba \u00ae\u00d8nh l\u00b5 : \u00ae\u00d8nh A, \u00ae\u00d8nh B, \u00ae\u00d8nh C. BC G Ba g\u00e3c l\u00b5 : G\u00e3c \u00ae\u00d8nh A, c\u00b9nh AB v\u00b5 AC (g\u00e4i t\u00bet l\u00b5 g\u00e3c A) ; G\u00e3c \u00ae\u00d8nh B, c\u00b9nh BA v\u00b5 BC (g\u00e4i t\u00bet l\u00b5 g\u00e3c B) ; G\u00e3c \u00ae\u00d8nh C, c\u00b9nh CA v\u00b5 CB (g\u00e4i t\u00bet l\u00b5 g\u00e3c C). H\u00d7nh tam gi\u00b8c c\u00e3 ba H\u00d7nh tam gi\u00b8c c\u00e3 m\u00e9t H\u00d7nh tam gi\u00b8c c\u00e3 g\u00e3c nh\u00e4n g\u00e3c t\u00ef v\u00b5 hai g\u00e3c nh\u00e4n m\u00e9t g\u00e3c vu\u00abng v\u00b5 hai g\u00e3c nh\u00e4n (g\u00e4i l\u00b5 h\u00d7nh b) \u00a7\u00b8y v\u00b5 \u00ae\u00f0\u00eang cao A tam gi\u00b8c vu\u00abng) BH C BC l\u00b5 \u00ae\u00b8y, AH l\u00b5 \u00ae\u00f0\u00eang cao \u00f8ng v\u00edi \u00ae\u00b8y BC. \u00a7\u00e9 d\u00b5i AH l\u00b5 chi\u00d2u cao. 85","AA A BH C HB C BC AH l\u00b5 \u00ae\u00f0\u00eang cao AH l\u00b5 \u00ae\u00f0\u00eang cao AB l\u00b5 \u00ae\u00f0\u00eang cao \u00f8ng v\u00edi \u00ae\u00b8y BC \u00f8ng v\u00edi \u00ae\u00b8y BC \u00f8ng v\u00edi \u00ae\u00b8y BC 1 Vi\u00d5t t\u00aan ba g\u00e3c v\u00b5 ba c\u00b9nh c\u00f1a m\u00e7i h\u00d7nh tam gi\u00b8c d\u00f0\u00edi \u00ae\u00a9y : DM A B CE GK N 2 H\u00b7y ch\u00d8 ra \u00ae\u00b8y v\u00b5 \u00ae\u00f0\u00eang cao t\u00f0\u00acng \u00f8ng \u00ae\u00f0\u00eec v\u00cf trong m\u00e7i h\u00d7nh tam gi\u00b8c d\u00f0\u00edi \u00ae\u00a9y : AD P H G N A MQ B C KE EB D 3 So s\u00b8nh di\u00d6n t\u00ddch c\u00f1a : HC a) H\u00d7nh tam gi\u00b8c AED v\u00b5 h\u00d7nh tam gi\u00b8c EDH. b) H\u00d7nh tam gi\u00b8c EBC v\u00b5 h\u00d7nh tam gi\u00b8c EHC. c) H\u00d7nh ch\u00f7 nh\u00cbt ABCD v\u00b5 h\u00d7nh tam gi\u00b8c EDC. 86","Di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c \u2212 Cho hai h\u00d7nh tam gi\u00b8c b\u00bbng nhau (xem h\u00d7nh v\u00cf). \u2212 L\u00cay m\u00e9t h\u00d7nh tam gi\u00b8c \u00ae\u00e3, c\u00bet theo \u00ae\u00f0\u00eang cao \u00ae\u00d3 th\u00b5nh hai m\u00b6nh tam gi\u00b8c 1 v\u00b5 2. \u2212 Gh\u00d0p hai m\u00b6nh 1 v\u00b5 2 v\u00b5o h\u00d7nh tam gi\u00b8c c\u00dfn l\u00b9i \u00ae\u00d3 \u00ae\u00f0\u00eec h\u00d7nh ch\u00f7 nh\u00cbt ABCD (xem h\u00d7nh v\u00cf). \u00a7-\u00eang AE B c\u00bet 1 2 12 DH C D\u00f9a v\u00b5o h\u00d7nh v\u00cf ta c\u00e3 : H\u00d7nh ch\u00f7 nh\u00cbt ABCD c\u00e3 chi\u00d2u d\u00b5i b\u00bbng \u00ae\u00e9 d\u00b5i \u00ae\u00b8y DC c\u00f1a h\u00d7nh tam gi\u00b8c EDC, c\u00e3 chi\u00d2u r\u00e9ng b\u00bbng chi\u00d2u cao EH c\u00f1a h\u00d7nh tam gi\u00b8c EDC. Di\u00d6n t\u00ddch h\u00d7nh ch\u00f7 nh\u00cbt ABCD g\u00cap 2 l\u00c7n di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c EDC. Di\u00d6n t\u00ddch h\u00d7nh ch\u00f7 nh\u00cbt ABCD l\u00b5 DC \u00d7 AD = DC \u00d7 EH. V\u00cby di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c EDC l\u00b5 . Mu\u00e8n t\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c ta l\u00cay \u00ae\u00e9 d\u00b5i \u00ae\u00b8y nh\u00a9n v\u00edi chi\u00d2u cao (c\u00efng m\u00e9t \u00ae\u00acn v\u00de \u00aeo) r\u00e5i chia cho 2. S= h (S l\u00b5 di\u00d6n t\u00ddch, a l\u00b5 \u00ae\u00e9 d\u00b5i \u00ae\u00b8y, h l\u00b5 chi\u00d2u cao) a 87","1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c c\u00e3 : a) \u00a7\u00e9 d\u00b5i \u00ae\u00b8y l\u00b5 8cm v\u00b5 chi\u00d2u cao l\u00b5 6cm. b) \u00a7\u00e9 d\u00b5i \u00ae\u00b8y l\u00b5 2,3dm v\u00b5 chi\u00d2u cao l\u00b5 1,2dm. 2 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c c\u00e3 : a) \u00a7\u00e9 d\u00b5i \u00ae\u00b8y l\u00b5 5m v\u00b5 chi\u00d2u cao l\u00b5 24dm. b) \u00a7\u00e9 d\u00b5i \u00ae\u00b8y l\u00b5 42,5m v\u00b5 chi\u00d2u cao l\u00b5 5,2m. Luy\u00d6n t\u00cbp 1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c c\u00e3 \u00ae\u00e9 d\u00b5i \u00ae\u00b8y l\u00b5 a v\u00b5 chi\u00d2u cao l\u00b5 h : a) a = 30,5dm v\u00b5 h = 12dm. b) a = 16dm v\u00b5 h = 5,3m. 2 H\u00b7y ch\u00d8 ra \u00ae\u00b8y v\u00b5 \u00ae\u00f0\u00eang cao t\u00f0\u00acng \u00f8ng \u00ae\u00b7 c\u00e3 trong m\u00e7i h\u00d7nh tam gi\u00b8c vu\u00abng d\u00f0\u00edi \u00ae\u00a9y : B D A CE G 3 a) T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c vu\u00abng ABC. A 3cm B 4cm C D b) T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c vu\u00abng DEG. 5cm 3cm EG 88","4 a) \u00a7o \u00ae\u00e9 d\u00b5i c\u00b8c c\u00b9nh c\u00f1a h\u00d7nh ch\u00f7 nh\u00cbt A B ABCD r\u00e5i t\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c ABC. b) \u00a7o \u00ae\u00e9 d\u00b5i c\u00b8c c\u00b9nh c\u00f1a h\u00d7nh ch\u00f7 nh\u00cbt D C MNPQ v\u00b5 \u00ae\u00e9 d\u00b5i c\u00b9nh ME. T\u00ddnh : ME N \u2212 T\u00e6ng di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c MQE v\u00b5 Q P di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c NEP. \u2212 Di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c EQP. Luy\u00d6n t\u00cbp chung Ph\u00c7n 1. M\u00e7i b\u00b5i t\u00cbp d\u00f0\u00edi \u00ae\u00a9y c\u00e3 n\u00aau k\u00ccm theo m\u00e9t s\u00e8 c\u00a9u tr\u00b6 l\u00eai A, B, C, D (l\u00b5 \u00ae\u00b8p s\u00e8, k\u00d5t qu\u00b6 t\u00ddnh, ...). H\u00b7y khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : 1 Ch\u00f7 s\u00e8 3 trong s\u00e8 th\u00cbp ph\u00a9n 72,364 c\u00e3 gi\u00b8 tr\u00de l\u00b5 : A. 3 B. C. D. 2 Trong b\u00d3 c\u00e3 25 con c\u00b8, trong \u00ae\u00e3 c\u00e3 20 con c\u00b8 ch\u00d0p. T\u00d8 s\u00e8 ph\u00c7n tr\u00a8m c\u00f1a s\u00e8 c\u00b8 ch\u00d0p v\u00b5 s\u00e8 c\u00b8 trong b\u00d3 l\u00b5 : A. 5% B. 20% C. 80% D. 100% 3 2800g b\u00bbng bao nhi\u00aau ki-l\u00ab-gam ? A. 280kg B. 28kg C. 2,8kg D. 0,28kg 89","Ph\u00c7n 2 b) 95,64 \u2013 27,35 ; d) 77,5 : 2,5. 1 \u00a7\u00c6t t\u00ddnh r\u00e5i t\u00ddnh : a) 39,72 + 46,18 ; c) 31,05 \u00d7 2,6 ; 2 Vi\u00d5t s\u00e8 th\u00cbp ph\u00a9n th\u00ddch h\u00eep v\u00b5o ch\u00e7 ch\u00cam : a) 8m 5dm = ... m ; b) 8m2 5dm2 = ... m2. 3 Cho bi\u00d5t di\u00d6n t\u00ddch c\u00f1a h\u00d7nh ch\u00f7 nh\u00cbt ABCD l\u00b5 2400cm2 (xem h\u00d7nh v\u00cf). T\u00ddnh di\u00d6n t\u00ddch c\u00f1a h\u00d7nh tam gi\u00b8c MDC. A B 15cm M 25cm D C 4 T\u00d7m hai gi\u00b8 tr\u00de s\u00e8 c\u00f1a x sao cho : 3,9 < x < 4,1. 90","H\u00d7nh thang A B D C H\u00d7nh thang ABCD C\u00b8i thang H\u00d7nh thang ABCD c\u00e3 : G C\u00b9nh \u00ae\u00b8y AB v\u00b5 c\u00b9nh \u00ae\u00b8y DC. C\u00b9nh b\u00aan AD v\u00b5 c\u00b9nh b\u00aan BC. G Hai c\u00b9nh \u00ae\u00b8y l\u00b5 hai c\u00b9nh \u00ae\u00e8i di\u00d6n song song. H\u00d7nh thang c\u00e3 m\u00e9t c\u00c6p c\u00b9nh \u00ae\u00e8i di\u00d6n song song. AB DH C AH l\u00b5 \u00ae-\u00eang cao. \u00a7\u00e9 d\u00b5i AH l\u00b5 chi\u00d2u cao 1 Trong c\u00b8c h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y, h\u00d7nh n\u00b5o l\u00b5 h\u00d7nh thang ? H\u00d7nh 1 H\u00d7nh 2 H\u00d7nh 3 H\u00d7nh 4 H\u00d7nh 5 H\u00d7nh 6 91","2 Trong ba h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y, h\u00d7nh n\u00b5o c\u00e3 : H\u00d7nh 1 H\u00d7nh 2 H\u00d7nh 3 \u2212 B\u00e8n c\u00b9nh v\u00b5 b\u00e8n g\u00e3c ? \u2212 Hai c\u00c6p c\u00b9nh \u00ae\u00e8i di\u00d6n song song ? \u2212 Ch\u00d8 c\u00e3 m\u00e9t c\u00c6p c\u00b9nh \u00ae\u00e8i di\u00d6n song song ? \u2212 C\u00e3 b\u00e8n g\u00e3c vu\u00abng ? 3 V\u00cf th\u00aam hai \u00aeo\u00b9n th\u00bcng v\u00b5o m\u00e7i h\u00d7nh d\u00f0\u00edi \u00ae\u00a9y \u00ae\u00d3 \u00ae\u00f0\u00eec h\u00d7nh thang : a) b) 4 H\u00d7nh thang ABCD c\u00e3 nh\u00f7ng g\u00e3c n\u00b5o l\u00b5 g\u00e3c A B vu\u00abng ? C\u00b9nh b\u00aan n\u00b5o vu\u00abng g\u00e3c v\u00edi D C hai \u00ae\u00b8y ? H\u00d7nh thang c\u00e3 m\u00e9t c\u00b9nh b\u00aan vu\u00abng g\u00e3c v\u00edi hai \u00ae\u00b8y g\u00e4i l\u00b5 h\u00d7nh thang vu\u00abng. 92","Di\u00d6n t\u00ddch h\u00d7nh thang Cho h\u00d7nh thang ABCD v\u00b5 \u00aei\u00d3m M l\u00b5 trung \u00aei\u00d3m c\u00f1a c\u00b9nh BC. C\u00bet h\u00d7nh tam gi\u00b8c ABM r\u00e5i gh\u00d0p v\u00edi h\u00d7nh t\u00f8 gi\u00b8c AMCD (nh\u00f0 h\u00d7nh v\u00cf) ta \u00ae\u00f0\u00eec h\u00d7nh tam gi\u00b8c ADK. AB A M M DH C DH C K (A) D\u00f9a v\u00b5o h\u00d7nh v\u00cf ta c\u00e3 : (B) Di\u00d6n t\u00ddch h\u00d7nh thang ABCD b\u00bbng di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c ADK. Di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c ADK l\u00b5 . M\u00b5 . V\u00cby di\u00d6n t\u00ddch h\u00d7nh thang ABCD l\u00b5 . Di\u00d6n t\u00ddch h\u00d7nh thang b\u00bbng t\u00e6ng \u00ae\u00e9 d\u00b5i hai \u00ae\u00b8y nh\u00a9n v\u00edi chi\u00d2u cao (c\u00efng m\u00e9t \u00ae\u00acn v\u00de \u00aeo) r\u00e5i chia cho 2. S= (S l\u00b5 di\u00d6n t\u00ddch ; a, b l\u00b5 \u00ae\u00e9 d\u00b5i c\u00b8c c\u00b9nh \u00ae\u00b8y ; h l\u00b5 chi\u00d2u cao) 1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh thang, bi\u00d5t : a) \u00a7\u00e9 d\u00b5i hai \u00ae\u00b8y l\u00c7n l\u00f0\u00eet l\u00b5 12cm v\u00b5 8cm ; chi\u00d2u cao l\u00b5 5cm. b) \u00a7\u00e9 d\u00b5i hai \u00ae\u00b8y l\u00c7n l\u00f0\u00eet l\u00b5 9,4m v\u00b5 6,6m ; chi\u00d2u cao l\u00b5 10,5m. 93","2 T\u00ddnh di\u00d6n t\u00ddch m\u00e7i h\u00d7nh thang sau : b) 3cm a) 4cm 5cm 4cm 7cm 9cm 3 M\u00e9t th\u00f6a ru\u00e9ng h\u00d7nh thang c\u00e3 \u00ae\u00e9 d\u00b5i hai \u00ae\u00b8y l\u00c7n l\u00f0\u00eet l\u00b5 110m v\u00b5 90,2m. Chi\u00d2u cao b\u00bbng trung b\u00d7nh c\u00e9ng c\u00f1a hai \u00ae\u00b8y. T\u00ddnh di\u00d6n t\u00ddch th\u00f6a ru\u00e9ng \u00ae\u00e3. luy\u00d6n t\u00cbp 1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh thang c\u00e3 \u00ae\u00e9 d\u00b5i hai \u00ae\u00b8y l\u00c7n l\u00f0\u00eet l\u00b5 a v\u00b5 b, chi\u00d2u cao h : a) a = 14cm ; b = 6cm ; h = 7cm. b) a = m ; b = m ; h = m. c) a = 2,8m ; b = 1,8m ; h = 0,5m. 2 M\u00e9t th\u00f6a ru\u00e9ng h\u00d7nh thang c\u00e3 \u00ae\u00b8y l\u00edn 120m, \u00ae\u00b8y b\u00d0 b\u00bbng \u00ae\u00b8y l\u00edn. \u00a7\u00b8y b\u00d0 d\u00b5i h\u00acn chi\u00d2u cao 5m. Trung b\u00d7nh c\u00f8 100m2 thu ho\u00b9ch \u00ae\u00f0\u00eec 64,5kg th\u00e3c. T\u00ddnh s\u00e8 ki-l\u00ab-gam th\u00e3c thu ho\u00b9ch \u00ae\u00f0\u00eec tr\u00aan th\u00f6a ru\u00e9ng \u00ae\u00e3. 3 \u00a7\u00f3ng ghi \u00a7, sai ghi S : A 3cm M 3cm N 3cm B a) Di\u00d6n t\u00ddch c\u00b8c h\u00d7nh thang AMCD, MNCD, NBCD b\u00bbng nhau. b) Di\u00d6n t\u00ddch h\u00d7nh thang AMCD b\u00bbng di\u00d6n t\u00ddch h\u00d7nh ch\u00f7 nh\u00cbt ABCD. D C 94","Luy\u00d6n t\u00cbp chung 1 T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tam gi\u00b8c vu\u00abng c\u00e3 \u00ae\u00e9 d\u00b5i hai c\u00b9nh g\u00e3c vu\u00abng l\u00b5 : a) 3cm v\u00b5 4cm ; b) 2,5m v\u00b5 1,6m ; c) dm v\u00b5 dm. 2 Di\u00d6n t\u00ddch c\u00f1a h\u00d7nh thang ABED l\u00edn h\u00acn di\u00d6n t\u00ddch c\u00f1a h\u00d7nh tam gi\u00b8c BEC bao nhi\u00aau \u00ae\u00d2-xi-m\u00d0t vu\u00abng ? A 1,6dm B 1,2dm H E 1,3dm C D 2,5dm 3 Tr\u00aan m\u00e9t m\u00b6nh v\u00f0\u00ean h\u00d7nh thang (nh\u00f0 h\u00d7nh v\u00cf), ng\u00f0\u00eai ta s\u00f6 d\u00f4ng 30% di\u00d6n t\u00ddch \u00ae\u00d3 tr\u00e5ng \u00aeu \u00ae\u00f1 v\u00b5 25% di\u00d6n t\u00ddch \u00ae\u00d3 tr\u00e5ng chu\u00e8i. 50m 40m 70m a) H\u00e1i c\u00e3 th\u00d3 tr\u00e5ng \u00ae\u00f0\u00eec bao nhi\u00aau c\u00a9y \u00aeu \u00ae\u00f1, bi\u00d5t r\u00bbng tr\u00e5ng m\u00e7i c\u00a9y \u00aeu \u00ae\u00f1 c\u00c7n 1,5m2 \u00ae\u00cat ? b) H\u00e1i s\u00e8 c\u00a9y chu\u00e8i tr\u00e5ng \u00ae\u00f0\u00eec nhi\u00d2u h\u00acn s\u00e8 c\u00a9y \u00aeu \u00ae\u00f1 bao nhi\u00aau c\u00a9y, bi\u00d5t r\u00bbng tr\u00e5ng m\u00e7i c\u00a9y chu\u00e8i c\u00c7n 1m2 \u00ae\u00cat ? 95","h\u00d7nh tr\u00dfn. \u00ae\u00f0\u00eang tr\u00dfn O 2cm O H\u00d7nh tr\u00dfn \u00a7\u00c7u ch\u00d7 c\u00f1a com pa v\u00b9ch tr\u00aan t\u00ea gi\u00cay m\u00e9t \u00ae-\u00eang tr\u00dfn \u2212 N\u00e8i t\u00a9m O v\u00edi m\u00e9t \u00aei\u00d3m A tr\u00aan \u00ae\u00f0\u00eang tr\u00dfn. C \u00a7o\u00b9n th\u00bcng OA l\u00b5 b\u00b8n k\u00ddnh c\u00f1a h\u00d7nh tr\u00dfn. T\u00cat c\u00b6 c\u00b8c b\u00b8n k\u00ddnh c\u00f1a m\u00e9t h\u00d7nh tr\u00dfn \u00ae\u00d2u b\u00bbng A O nhau : OA = OB = OC. B \u2212 \u00a7o\u00b9n th\u00bcng MN n\u00e8i hai \u00aei\u00d3m M, N c\u00f1a \u00ae\u00f0\u00eang M tr\u00dfn v\u00b5 \u00aei qua t\u00a9m O l\u00b5 \u00ae\u00f0\u00eang k\u00ddnh c\u00f1a N h\u00d7nh tr\u00dfn. O Trong m\u00e9t h\u00d7nh tr\u00dfn, \u00ae\u00f0\u00eang k\u00ddnh d\u00b5i g\u00cap 2 l\u00c7n b\u00b8n k\u00ddnh. 1 V\u00cf h\u00d7nh tr\u00dfn c\u00e3 : b) \u00a7\u00f0\u00eang k\u00ddnh 5cm. a) B\u00b8n k\u00ddnh 3cm ; 2 Cho \u00aeo\u00b9n th\u00bcng AB = 4cm. H\u00b7y v\u00cf hai h\u00d7nh tr\u00dfn t\u00a9m A v\u00b5 t\u00a9m B \u00ae\u00d2u c\u00e3 b\u00b8n k\u00ddnh 2cm. 96","3 V\u00cf theo m\u00c9u : Chu vi h\u00d7nh tr\u00dfn G L\u00cay b\u00d7a c\u00f8ng, v\u00cf v\u00b5 c\u00bet m\u00e9t h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh 2cm. Ta \u00ae\u00b8nh d\u00cau m\u00e9t \u00aei\u00d3m A tr\u00aan \u00ae\u00f0\u00eang tr\u00dfn. \u00a7\u00c6t \u00aei\u00d3m A tr\u00efng v\u00edi v\u00b9ch 0 tr\u00aan m\u00e9t c\u00b8i th\u00f0\u00edc c\u00e3 v\u00b9ch chia x\u00a8ng-ti-m\u00d0t v\u00b5 mi- li-m\u00d0t. Ta cho h\u00d7nh tr\u00dfn l\u00a8n m\u00e9t v\u00dfng tr\u00aan th\u00f0\u00edc \u00ae\u00e3 th\u00d7 th\u00cay r\u00bbng \u00aei\u00d3m A l\u00a8n \u00ae\u00d5n v\u00de tr\u00dd \u00aei\u00d3m B n\u00bbm gi\u00f7a v\u00de tr\u00dd 12,5cm v\u00b5 12,6cm tr\u00aan th\u00f0\u00edc k\u00ce. \u00a7\u00e9 d\u00b5i c\u00f1a \u00ae\u00f0\u00eang tr\u00dfn b\u00b8n k\u00ddnh 2cm ch\u00ddnh l\u00b5 \u00ae\u00e9 d\u00b5i c\u00f1a \u00aeo\u00b9n th\u00bcng AB. \u00a7\u00e9 d\u00b5i c\u00f1a m\u00e9t \u00ae\u00f0\u00eang tr\u00dfn g\u00e4i l\u00b5 chu vi c\u00f1a h\u00d7nh tr\u00dfn \u00ae\u00e3. Nh\u00f0 v\u00cby h\u00d7nh tr\u00dfn b\u00b8n k\u00ddnh 2cm c\u00e3 chu vi trong kho\u00b6ng 12,5cm \u00ae\u00d5n 12,6cm ho\u00c6c h\u00d7nh tr\u00dfn \u00ae\u00f0\u00eang k\u00ddnh 4cm c\u00e3 chu vi trong kho\u00b6ng 12,5cm \u00ae\u00d5n 12,6cm. AB 0 cm 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Chu vi h\u00d7nh tr\u00dfn Trong to\u00b8n h\u00e4c, ng\u00f0\u00eai ta c\u00e3 th\u00d3 t\u00ddnh chu vi h\u00d7nh tr\u00dfn c\u00e3 \u00ae\u00f0\u00eang k\u00ddnh 4cm b\u00bbng c\u00b8ch nh\u00a9n \u00ae\u00f0\u00eang k\u00ddnh 4cm v\u00edi s\u00e8 3,14 : 4 \u00d7 3,14 = 12,56 (cm) 97","Mu\u00e8n t\u00ddnh chu vi c\u00f1a h\u00d7nh tr\u00dfn ta l\u00cay \u00ae\u00f0\u00eang k\u00ddnh nh\u00a9n v\u00edi s\u00e8 3,14. C = d \u00d7 3,14 (C l\u00b5 chu vi h\u00d7nh tr\u00dfn, d l\u00b5 \u00ae\u00f0\u00eang k\u00ddnh h\u00d7nh tr\u00dfn). Ho\u00c6c : Mu\u00e8n t\u00ddnh chu vi c\u00f1a h\u00d7nh tr\u00dfn ta l\u00cay 2 l\u00c7n b\u00b8n k\u00ddnh nh\u00a9n v\u00edi s\u00e8 3,14. C = r \u00d7 2 \u00d7 3,14 r (C l\u00b5 chu vi h\u00d7nh tr\u00dfn, r l\u00b5 b\u00b8n k\u00ddnh h\u00d7nh tr\u00dfn). O V\u00dd d\u00f4 1 : T\u00ddnh chu vi h\u00d7nh tr\u00dfn c\u00e3 \u00ae\u00f0\u00eang k\u00ddnh 6cm. Chu vi h\u00d7nh tr\u00dfn l\u00b5 : 6 \u00d7 3,14 = 18,84 (cm) V\u00dd d\u00f4 2 : T\u00ddnh chu vi h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh 5cm. Chu vi h\u00d7nh tr\u00dfn l\u00b5 : 5 \u00d7 2 \u00d7 3,14 = 31,4 (cm) 1 T\u00ddnh chu vi h\u00d7nh tr\u00dfn c\u00e3 \u00ae\u00f0\u00eang k\u00ddnh d : a) d = 0,6cm ; b) d = 2,5dm ; c) d = m. 2 T\u00ddnh chu vi h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh r : a) r = 2,75cm ; b) r = 6,5dm ; c) r = m. 3 M\u00e9t b\u00b8nh xe \u00ab t\u00ab c\u00e3 \u00ae\u00f0\u00eang k\u00ddnh l\u00b5 0,75m. T\u00ddnh chu vi c\u00f1a b\u00b8nh xe \u00ae\u00e3. 98","Luy\u00d6n t\u00cbp 1 T\u00ddnh chu vi h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh r : a) r = 9m ; b) r = 4,4dm ; c) r = cm. 2 a) T\u00ddnh \u00ae\u00f0\u00eang k\u00ddnh h\u00d7nh tr\u00dfn c\u00e3 chu vi C = 15,7m. b) T\u00ddnh b\u00b8n k\u00ddnh h\u00d7nh tr\u00dfn c\u00e3 chu vi C = 18,84dm. 3 \u00a7\u00f0\u00eang k\u00ddnh c\u00f1a m\u00e9t b\u00b8nh xe \u00ae\u00b9p l\u00b5 0,65m. a) T\u00ddnh chu vi c\u00f1a b\u00b8nh xe \u00ae\u00e3. b) Ng\u00f0\u00eai \u00aei xe \u00ae\u00b9p s\u00cf \u00aei \u00ae\u00f0\u00eec bao nhi\u00aau m\u00d0t n\u00d5u b\u00b8nh xe l\u00a8n tr\u00aan m\u00c6t \u00ae\u00cat \u00ae\u00f0\u00eec 10 v\u00dfng, \u00ae\u00f0\u00eec 100 v\u00dfng ? 4 Khoanh v\u00b5o ch\u00f7 \u00ae\u00c6t tr\u00f0\u00edc c\u00a9u tr\u00b6 l\u00eai \u00ae\u00f3ng : l\u00b5 : Cho n\u00f6a h\u00d7nh tr\u00dfn (xem h\u00d7nh v\u00cf). Chu vi h\u00d7nh A. 18,84cm 6cm B. 9,42cm H\u00d7nh C. 24,84cm D. 15,42cm Di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn Mu\u00e8n t\u00ddnh di\u00d6n t\u00ddch c\u00f1a h\u00d7nh tr\u00dfn ta l\u00cay b\u00b8n k\u00ddnh nh\u00a9n v\u00edi b\u00b8n k\u00ddnh r\u00e5i nh\u00a9n v\u00edi s\u00e8 3,14. S = r \u00d7 r \u00d7 3,14 (S l\u00b5 di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn, r l\u00b5 b\u00b8n k\u00ddnh h\u00d7nh tr\u00dfn). V\u00dd d\u00f4 : T\u00ddnh di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn c\u00e3 b\u00b8n k\u00ddnh 2dm. Di\u00d6n t\u00ddch h\u00d7nh tr\u00dfn l\u00b5 : 2 \u00d7 2 \u00d7 3,14 = 12,56 (dm2) 99"]