Sau \u0111\u00e2y ta lu\u00f4n k\u00ed hi\u1ec7u s\u1ed1 c\u00e1c \u0111\u1ec9nh, c\u1ea1nh, m\u1eb7t c\u1ee7a m\u1ed9t h\u00ecnh \u0111a di\u1ec7n l\u00e0 d, c, m.<\/p>\n
C\u00e2u 1:<\/b>\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau, m\u1ec7nh \u0111\u1ec1 n\u00e0o \u0111\u00fang?<\/p>\n
Kh\u1ed1i \u0111a di\u1ec7n c\u00f3 c\u00e1c m\u1eb7t l\u00e0 nh\u1eefng tam gi\u00e1c th\u00ec:<\/p>\n
A. S\u1ed1 m\u1eb7t v\u00e0 s\u1ed1 \u0111\u1ec9nh c\u1ee7a n\u00f3 b\u1eb1ng nhau<\/p>\n
B. S\u1ed1 m\u1eb7t v\u00e0 s\u1ed1 c\u1ea1nh c\u1ee7a n\u00f3 b\u1eb1ng nhau<\/p>\n
C. S\u1ed1 m\u1eb7t c\u1ee7a n\u00f3 l\u00e0 m\u1ed9t s\u1ed1 ch\u1eb5n<\/p>\n
D. S\u1ed1 m\u1eb7t c\u1ee7a n\u00f3 l\u00e0 m\u1ed9t s\u1ed1 l\u1ebb<\/p>\n
C\u00e2u 2:<\/b>\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau, m\u1ec7nh \u0111\u1ec1 n\u00e0o\u00a0sai<\/b>\u00a0?<\/p>\n
A. T\u1ed3n t\u1ea1i m\u1ed9t h\u00ecnh \u0111a di\u1ec7n c\u00f3 s\u1ed1 c\u1ea1nh b\u1eb1ng 7<\/p>\n
B. T\u1ed3n t\u1ea1i m\u1ed9t h\u00ecnh \u0111a di\u1ec7n c\u00f3 s\u1ed1 c\u1ea1nh nh\u1ecf h\u01a1n 7<\/p>\n
C. S\u1ed1 c\u1ea1nh c\u1ee7a m\u1ed9t h\u00ecnh \u0111a di\u1ec7n lu\u00f4n l\u1edbn h\u01a1n ho\u1eb7c b\u1eb1ng 6<\/p>\n
D. T\u1ed3n t\u1ea1i m\u1ed9t h\u00ecnh \u0111a di\u1ec7n c\u00f3 s\u1ed1 c\u1ea1nh l\u1edbn h\u01a1n 7<\/p>\n
C\u00e2u 3:<\/b>\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau, m\u1ec7nh \u0111\u1ec1 n\u00e0o \u0111\u00fang?<\/p>\n
A. Trong m\u1ed9t h\u00ecnh \u0111a di\u1ec7n t\u1ed5ng c\u1ee7a s\u1ed1 m\u1eb7t v\u00e0 s\u1ed1 c\u1ea1nh nh\u1ecf h\u01a1n s\u1ed1 \u0111\u1ec9nh.<\/p>\n
B. Trong m\u1ed9t h\u00ecnh \u0111a di\u1ec7n t\u1ed5ng c\u1ee7a s\u1ed1 m\u1eb7t v\u00e0 s\u1ed1 \u0111\u1ec9nh l\u1edbn h\u01a1n s\u1ed1 c\u1ea1nh<\/p>\n
C. Trong m\u1ed9t h\u00ecnh \u0111a di\u1ec7n t\u1ed5ng s\u1ed1 c\u1ea1nh v\u00e0 s\u1ed1 \u0111\u1ec9nh nh\u1ecf h\u01a1n s\u1ed1 m\u1eb7t<\/p>\n
D. T\u1ed3n t\u1ea1i m\u1ed9t h\u00ecnh \u0111a di\u1ec7n c\u00f3 t\u1ed5ng c\u1ee7a s\u1ed1 m\u1eb7t v\u00e0 s\u1ed1 \u0111\u1ec9nh nh\u1ecf h\u01a1n s\u1ed1 c\u1ea1nh<\/p>\n
C\u00e2u 4:<\/b>\u00a0Trong c\u00e1c h\u00ecnh sau \u0111\u00e2y, h\u00ecnh n\u00e0o l\u00e0 h\u00ecnh \u0111a di\u1ec7n?<\/p>\n
<\/p>\n
<\/p>\n
C\u00e2u 5:<\/b>\u00a0Trong c\u00e1c h\u00ecnh sau \u0111\u00e2y, h\u00ecnh n\u00e0o kh\u00f4ng ph\u1ea3i l\u00e0 h\u00ecnh \u0111a di\u1ec7n?<\/p>\n
<\/p>\n
<\/p>\n
C\u00e2u 6:<\/b>\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau, m\u1ec7nh \u0111\u1ec1 n\u00e0o \u0111\u00fang?<\/p>\n
A. M\u1ed7i h\u00ecnh \u0111a di\u1ec7n c\u00f3 \u00edt nh\u1ea5t 8 m\u1eb7t<\/p>\n
B. M\u1ed7i h\u00ecnh \u0111a di\u1ec7n c\u00f3 \u00edt nh\u1ea5t 6 m\u1eb7t<\/p>\n
C. M\u1ed7i h\u00ecnh \u0111a di\u1ec7n c\u00f3 \u00edt nh\u1ea5t 5 m\u1eb7t<\/p>\n
D. M\u1ed7i h\u00ecnh \u0111a di\u1ec7n c\u00f3 \u00edt nh\u1ea5t 4 m\u1eb7t<\/p>\n
H\u01b0\u1edbng d\u1eabn gi\u1ea3i v\u00e0 \u0110\u00e1p \u00e1n<\/b><\/p>\n C\u00e2u 1:<\/b><\/p>\n C\u00e1ch 1: Ta c\u00f3 th\u1ec3 d\u00f9ng c\u00e1c ph\u1ea3n v\u00ed d\u1ee5 \u0111\u1ec3 lo\u1ea1i d\u1ea7n c\u00e1c m\u1ec7nh \u0111\u1ec3 sai. T\u1ee9 di\u1ec7n (c\u00f3 4 \u0111\u1ec9nh, 4 m\u1eb7t v\u00e0 6 c\u1ea1nh) ta th\u1ea5y ngay m\u1ec7nh \u0111\u1ec1 B v\u00e0 D sai.<\/p>\n T\u1eeb h\u00ecnh b\u00e1t di\u1ec7n \u0111\u1ec1u (c\u00f3 6 \u0111\u1ec9nh, 8 m\u1eb7t) ta th\u1ea5y m\u1ec7nh \u0111\u1ec1 A sai.<\/p>\n V\u1eady C l\u00e0 m\u1ec7nh \u0111\u1ec1 \u0111\u00fang.<\/p>\n C\u00e1ch 2: Ta c\u00f3 th\u1ec3 v\u1eadn d\u1ee5ng c\u00f4ng th\u1ee9c (2) \u1edf tr\u00ean. Thay p = 3 ta c\u00f3: 3m = 2c.<\/p>\n V\u1eady m ph\u1ea3i l\u00e0 s\u1ed1 ch\u1eb5n.<\/p>\n Do \u0111\u00f3 C l\u00e0 m\u1ec7nh \u0111\u1ec1 \u0111\u00fang.<\/p>\n C\u00e2u 2:<\/b><\/p>\n C\u00e1ch 1 : C\u00e2u C lu\u00f4n \u0111\u00fang ( theo l\u00ed thuy\u1ebft).<\/p>\n T\u1eeb h\u00ecnh t\u1ee9 di\u1ec7n suy ra c\u00e2u B \u0111\u00fang.<\/p>\n T\u1eeb h\u00ecnh h\u1ed9p suy ra c\u00e2u D \u0111\u00fang.<\/p>\n V\u1eady c\u00e2u A sai.<\/p>\n C\u00e1ch 2 : N\u1ebfu m = 4 th\u00ec c = 6. Do \u0111\u00f3 n\u1ebfu c = 7 th\u00ec m \u2265 5.<\/p>\n V\u00ec m\u1ed7i m\u1eb7t c\u00f3 \u00edt nh\u1ea5t 3 c\u1ea1nh v\u00e0 m\u1ed7i c\u1ea1nh l\u00e0 c\u1ea1nh chung c\u1ee7a \u0111\u00fang 2 m\u1eb7t, n\u00ean c \u2265 (5.3)\/2 \u2265 7 v\u00f4 l\u00ed.<\/p>\n V\u1eady m\u1ec7nh \u0111\u1ec1 A sai<\/p>\n C\u00e2u 3:<\/b><\/p>\n C\u00e1ch 1: D\u1ec5 t\u00ecm c\u00e1c ph\u1ea3n v\u00ed d\u1ee5 \u0111\u1ec3 t\u1ea1o m\u1ec7nh \u0111\u1ec1 A, C, D<\/p>\n C\u00e1ch 2: Ta c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng c\u00f4ng th\u1ee9c \u01a0le: d + m \u2013 2 = c suy ra B l\u00e0 m\u1ec7nh \u0111\u1ec1 \u0111\u00fang.<\/p>\n C\u00e2u 4:<\/b><\/p>\n H\u00ecnh A c\u00f3 m\u1ed9t c\u1ea1nh l\u00e0 c\u1ea1nh chung c\u1ee7a b\u1ed1n m\u1eb7t, c\u00e1c h\u00ecnh B, D c\u00f3 c\u1ea1nh ch\u1ec9 thu\u1ed9c m\u1ed9t m\u1eb7t n\u00ean kh\u00f4ng ph\u1ea3i h\u00ecnh \u0111a di\u1ec7n.<\/p>\n C\u00e2u 5:<\/b><\/p>\n C\u00e1c b\u00e0i t\u1eadp 3,4,5 d\u00f9ng c\u00f4ng th\u1ee9c (1)<\/p>\n","protected":false},"excerpt":{"rendered":" Sau \u0111\u00e2y ta lu\u00f4n k\u00ed hi\u1ec7u s\u1ed1 c\u00e1c \u0111\u1ec9nh, c\u1ea1nh, m\u1eb7t c\u1ee7a m\u1ed9t h\u00ecnh \u0111a di\u1ec7n l\u00e0 d, c, m. C\u00e2u 1:\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau, m\u1ec7nh \u0111\u1ec1 n\u00e0o \u0111\u00fang? Kh\u1ed1i \u0111a di\u1ec7n c\u00f3 c\u00e1c m\u1eb7t l\u00e0 nh\u1eefng tam gi\u00e1c th\u00ec: A. S\u1ed1 m\u1eb7t v\u00e0 s\u1ed1 \u0111\u1ec9nh c\u1ee7a n\u00f3 b\u1eb1ng nhau B. S\u1ed1 m\u1eb7t v\u00e0 […]<\/p>\n","protected":false},"author":3,"featured_media":28966,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[157],"tags":[1450,1448],"yoast_head":"\n\n\n
\n 1-C<\/td>\n 2-A<\/td>\n 3-B<\/td>\n 4-C<\/td>\n 5-D<\/td>\n 6-D<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n