B\u00e0i 1 (trang 119 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau \u0111\u00e2y m\u1ec7nh \u0111\u1ec1 n\u00e0o l\u00e0 \u0111\u00fang?<\/p>\n
a) \u0110\u01b0\u1eddng th\u1eb3ng \u0394 l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a hai \u0111\u01b0\u1eddng th\u1eb3ng a v\u00e0 b n\u1ebfu \u0394 \u22a5a v\u00e0 \u0394 \u22a5b.<\/p>\n
b) G\u1ecdi (P) l\u00e0 m\u1eb7t ph\u1eb3ng song song v\u1edbi c\u1ea3 hai \u0111\u01b0\u1eddng th\u1eb3ng a v\u00e0 b ch\u00e9o nhau th\u00ec \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a a v\u00e0 b lu\u00f4n lu\u00f4n vu\u00f4ng g\u00f3c v\u1edbi (P).<\/p>\n
c) G\u1ecdi \u0394 l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a hai \u0111\u01b0\u1eddng th\u1eb3ng ch\u00e9o nhau a v\u00e0 b th\u00ec \u0394 l\u00e0 giao tuy\u1ebfn c\u1ee7a hai m\u1eb7t ph\u1eb3ng (a, \u0394) v\u00e0 (b, \u0394).<\/p>\n
d) Cho hai \u0111\u01b0\u1eddng th\u1eb3ng ch\u00e9o nhau a v\u00e0 b. \u0110\u01b0\u1eddng th\u1eb3ng n\u00e0o \u0111i qua m\u1ed9t \u0111i\u1ec3m M tr\u00ean a \u0111\u1ed3ng th\u1eddi c\u1eaft b t\u1ea1i N v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi b th\u00ec \u0111\u00f3 l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a a v\u00e0 b.<\/p>\n
e) \u0110\u01b0\u1eddng vu\u00f4ng g\u00f3c chung \u0394 c\u1ee7a hai \u0111\u01b0\u1eddng th\u1eb3ng ch\u00e9o nhau a v\u00e0 b n\u1eb1m trong m\u1eb7t ph\u1eb3ng ch\u1ee9a \u0111\u01b0\u1eddng n\u00e0y v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi \u0111\u01b0\u1eddng kia.<\/p>\n
L\u1eddi gi\u1ea3i:<\/b><\/p>\n
a) Sai, \u0111\u00fang l\u00e0 “\u0110\u01b0\u1eddng th\u1eb3ng \u0394 l\u00e0 \u0111\u01b0\u1eddng th\u1eb3ng vu\u00f4ng g\u00f3c chung c\u1ee7a hai \u0111\u01b0\u1eddng th\u1eb3ng ch\u00e9o nhau a v\u00e0 b n\u1ebfu \u0394 c\u1eaft c\u1ea3 a v\u00e0 b, \u0111\u1ed3ng th\u1eddi \u0394 \u22a5a v\u00e0 \u0394 \u22a5b”<\/p>\n
b) \u0110\u00fang<\/p>\n
c) \u0110\u00fang<\/p>\n
d) Sai<\/p>\n
e) Sai.<\/p>\n
B\u00e0i 2 (trang 119 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Cho t\u1ee9 di\u1ec7n S.ABCD c\u00f3 SA vu\u00f4ng g\u00f3c v\u1edbi m\u1eb7t ph\u1eb3ng<\/p>\n
a) Ch\u1ee9ng minh ba \u0111\u01b0\u1eddng th\u1eb3ng AH, SK, BC \u0111\u1ed3ng quy.<\/p>\n
b) Ch\u1ee9ng minh r\u1eb1ng SC vu\u00f4ng g\u00f3c v\u1edbi m\u1eb7t ph\u1eb3ng (BHK) v\u00e0 HK vu\u00f4ng g\u00f3c v\u1edbi m\u1eb7t ph\u1eb3ng (SBC).<\/p>\n
c) X\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a BC v\u00e0 SA.<\/p>\n
L\u1eddi gi\u1ea3i:<\/b><\/p>\n
<\/p>\n
<\/p>\n
B\u00e0i 3 (trang 119 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Cho h\u00ecnh l\u1eadp ph\u01b0\u01a1ng ABCD.A‘<\/sup>B‘<\/sup>C‘<\/sup>D‘<\/sup>\u00a0c\u1ea1nh a. Ch\u1ee9ng minh r\u1eb1ng c\u00e1c kho\u1ea3ng c\u00e1ch t\u1eeb c\u00e1c \u0111i\u1ec3m B, C, D, A‘<\/sup>, B‘<\/sup>\u00a0v\u00e0 D‘<\/sup>\u00a0\u0111\u1ebfn \u0111\u01b0\u1eddng ch\u00e9o AC‘<\/sup>\u00a0\u0111\u1ec1u b\u1eb1ng nhau. T\u00ednh kho\u1ea3ng c\u00e1ch \u0111\u00f3.<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n <\/p>\n B\u00e0i 4 (trang 119 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Cho h\u00ecnh h\u1ed9p ch\u1eef nh\u1eadt ABCD.A‘<\/sup>B‘<\/sup>C‘<\/sup>D‘<\/sup>\u00a0c\u00f3 AB = a, BC = b, CC‘<\/sup>\u00a0= c.<\/p>\n a) T\u00ednh kho\u1ea3ng c\u00e1ch t\u1eeb B \u0111\u1ebfn m\u1eb7t ph\u1eb3ng (ACC‘<\/sup>A‘<\/sup>).<\/p>\n b) T\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa hai \u0111\u01b0\u1eddng th\u1eb3ng BB‘<\/sup>\u00a0v\u00e0 AC‘<\/sup>.<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n <\/p>\n B\u00e0i 5 (trang 119 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Cho h\u00ecnh l\u1eadp ph\u01b0\u01a1ng ABCD.A’B’C’D’<\/p>\n a) Ch\u1ee9ng minh r\u1eb1ng B’D vu\u00f4ng g\u00f3c v\u1edbi m\u1eb7t ph\u1eb3ng (BA’C’)<\/p>\n b) T\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa hai m\u1eb7t ph\u1eb3ng (BA’C’) v\u00e0 (ACD)<\/p>\n c) T\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa hai \u0111\u01b0\u1eddng th\u1eb3ng BC’ v\u00e0 CD’<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n <\/p>\n B\u00e0i 6 (trang 119 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Ch\u1ee9ng minh r\u1eb1ng n\u1ebfu \u0111\u01b0\u1eddng th\u1eb3ng n\u1ed1i trung \u0111i\u1ec3m hai c\u1ea1nh AB v\u00e0 CD c\u1ee7a t\u1ee9 di\u1ec7n ABCD l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a AB v\u00e0 CD th\u00ec AC = BD v\u00e0 AD = BC.<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n \\<\/p>\n <\/p>\n B\u00e0i 7 (trang 120 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Cho h\u00ecnh ch\u00f3p tam gi\u00e1c \u0111\u1ec1u S.ABC c\u00f3 c\u1ea1nh \u0111\u00e1y b\u1eb1ng 3a, c\u1ea1nh b\u00ean b\u1eb1ng 2a. T\u00ednh kho\u1ea3ng c\u00e1ch t\u1eeb S t\u1edbi m\u1eb7t \u0111\u00e1y (ABC).<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n B\u00e0i 8 (trang 120 SGK H\u00ecnh h\u1ecdc 11):<\/b>\u00a0Cho t\u1ee9 di\u1ec7n ABCD c\u1ea1nh a. T\u00ednh kho\u1ea3ng c\u00e1ch gi\u1eefa hai c\u1ea1nh \u0111\u1ed1i di\u1ec7n c\u1ee7a t\u1ee9 di\u1ec7n \u0111\u1ec1u \u0111\u00f3.<\/p>\n L\u1eddi gi\u1ea3i:<\/b><\/p>\n <\/p>\n <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":" B\u00e0i 1 (trang 119 SGK H\u00ecnh h\u1ecdc 11):\u00a0Trong c\u00e1c m\u1ec7nh \u0111\u1ec1 sau \u0111\u00e2y m\u1ec7nh \u0111\u1ec1 n\u00e0o l\u00e0 \u0111\u00fang? a) \u0110\u01b0\u1eddng th\u1eb3ng \u0394 l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c chung c\u1ee7a hai \u0111\u01b0\u1eddng th\u1eb3ng a v\u00e0 b n\u1ebfu \u0394 \u22a5a v\u00e0 \u0394 \u22a5b. b) G\u1ecdi (P) l\u00e0 m\u1eb7t ph\u1eb3ng song song v\u1edbi c\u1ea3 hai \u0111\u01b0\u1eddng th\u1eb3ng a v\u00e0 […]<\/p>\n","protected":false},"author":3,"featured_media":29405,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[1318],"tags":[1464,1463],"yoast_head":"\n