{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["20"],["20"],["110"]]],"list":[{"point":10,"width":50,"type_input":"","ques":"<span class='basic_left'> Cho tam gi\u00e1c ABC c\u00f3 $\\widehat{A} = 70^{o} $, c\u00e1c g\u00f3c $\\widehat{B} $ v\u00e0 $\\widehat{C} $ \u0111\u1ec1u nh\u1ecdn. D\u00f9ng th\u01b0\u1edbc th\u1eb3ng v\u00e0 eke v\u1ebd \u0111o\u1ea1n th\u1eb3ng \u0111i qua B v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi AC t\u1ea1i E, v\u1ebd \u0111o\u1ea1n th\u1eb3ng \u0111i qua C v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi AB t\u1ea1i F. <br\/> a) \u0110o c\u00e1c g\u00f3c: $\\widehat{ABE} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} \\\\ \\widehat{ACF} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} $ <br\/> b) G\u1ecdi H l\u00e0 giao \u0111i\u1ec3m c\u1ee7a BE v\u00e0 CF. \u0110o g\u00f3c $\\widehat{EHF} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o}$<\/center>","hint":"","explain":" H\u00ecnh v\u1ebd: <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-40.png' \/><\/center> <br\/><br\/><span class='basic_pink'> \u0110o \u0111\u01b0\u1ee3c: $ \\widehat{ABE} = 20^{o} \\\\ \\widehat{ACF} = 20^{o} \\\\ \\widehat{EHF} = 110^{o} $ <\/span><\/span> "}]}],"id_ques":1381},{"time":14,"part":[{"time":3,"title":" <span class='basic_left'> Cho $\\widehat{AOB} = 150^{o} $. V\u1ec1 ph\u00eda ngo\u00e0i c\u1ee7a g\u00f3c AOB v\u1ebd hai tia OC v\u00e0 OD theo th\u1ee9 t\u1ef1 vu\u00f4ng g\u00f3c v\u1edbi OA, OB. G\u1ecdi Ox l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c AOB, Oy l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia Ox. Khi \u0111\u00f3: <\/span>","title_trans":"","audio":"","temp":"matching","correct":[["2","4","1","3"]],"list":[{"point":10,"image":"","left":["$\\widehat{AOC} = $","$\\widehat{xOC} = $","$\\widehat{COy} = $","$\\widehat{BOy} = $"],"right":["$15^{o} $","$90^{o} $","$105^{o} $","$165^{o} $"],"top":100,"hint":"","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-46.png' \/><\/center> <span class='basic_left'> Ta c\u00f3: $OC \\perp OA $ n\u00ean $\\widehat{AOC} = 90^{o} $ <br\/> Ox l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c AOB n\u00ean $\\widehat{xOA} = \\dfrac{\\widehat{AOB}}{2} = \\dfrac{150^{o}}{2} = 75^{o} $ <br\/> Ox v\u00e0 OA thu\u1ed9c hai n\u1eeda m\u1eb7t ph\u1eb3ng \u0111\u1ed1i nhau b\u1edd OA n\u00ean tia OA n\u1eb1m gi\u1eefa hai tia Ox, OC do \u0111\u00f3: <br\/> $ \\widehat{xOC} = \\widehat{xOA} + \\widehat{AOC} = 75^{o} + 90^{o} = 165^{o}$ <br\/> Ox v\u00e0 Oy l\u00e0 hai tia \u0111\u1ed1i nhau n\u00ean $\\widehat{xOC} + \\widehat{COy} = 180^{o} \\\\ \\Rightarrow \\widehat{COy} = 180^{o} - 165^{o} = 15^{o} $ <br\/> T\u01b0\u01a1ng t\u1ef1 ta t\u00ednh \u0111\u01b0\u1ee3c $\\widehat{DOy} = 15^{o} $ <br\/> Suy ra $ \\widehat{BOy} = 90^{o} + 15^{o} = 105^{o}$ <\/span> <br\/> <span class='basic_pink'> V\u1eady: $\\widehat{AOC} = 90^{o} \\\\ \\widehat{xOC} = 165^{o} \\\\\\widehat{COy} = 15^{o} \\\\ \\widehat{BOy} = 105^{o} $<\/span>"}]}],"id_ques":1382},{"time":14,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"<span class='basic_left'> Cho g\u00f3c $\\widehat{AOB}$ b\u1eb1ng $130^{o} $. Trong g\u00f3c $\\widehat{AOB}$ v\u1ebd c\u00e1c tia OC, OD sao cho $OC \\perp OA, OD \\perp OB $ <br\/> S\u1ed1 \u0111o g\u00f3c $\\widehat{COD}$ l\u00e0? <\/span> ","select":[" A. $40^{o}$ "," B. $50^{o} $ "," C. $60^{o} $"," D. $90^{o} $"],"hint":"B\u01b0\u1edbc 1. T\u00ednh s\u1ed1 \u0111o g\u00f3c $\\widehat{BOC}$ <br\/> B\u01b0\u1edbc 2. T\u00ednh g\u00f3c $\\widehat{COD}$","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-11.png' \/><\/center> <span class='basic_left'> Ta c\u00f3 $OC \\perp OA \\Rightarrow \\widehat{AOC} = 90^{o} \\\\ OD \\perp OB \\Rightarrow \\widehat{BOD} = 90^{o} $ <br\/> Tia OC n\u1eb1m gi\u1eefa hai tia OA v\u00e0 OB n\u00ean <br\/> $\\widehat{AOC} + \\widehat{COB} = \\widehat{AOB} \\\\ \\Rightarrow \\widehat{COB} = \\widehat{AOB} - \\widehat{AOC} = 130^{o} - 90^{o} = 40^{o} $ <br\/> C\u00f3 $ \\widehat{COB} = 40^{o} < \\widehat{BOD} = 90^{o} $ n\u00ean tia OC n\u1eb1m gi\u1eefa hai tia OB v\u00e0 OD <br\/> $ \\Rightarrow \\widehat{BOC} + \\widehat{COD} = \\widehat{BOD} \\\\ \\Rightarrow \\widehat{COD} = \\widehat{BOD} - \\widehat{BOC} = 90^{o} - 40^{o} = 50^{o} $<\/span> <br\/><br\/><span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span><\/span> ","column":4}]}],"id_ques":1383},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["90"],["90"],["90"]]],"list":[{"point":10,"width":50,"type_input":"","ques":"<span class='basic_left'>V\u1ebd \u0111\u01b0\u1eddng th\u1eb3ng a. Tr\u00ean \u0111\u01b0\u1eddng th\u1eb3ng a v\u1ebd \u0111o\u1ea1n th\u1eb3ng AB = 4cm. V\u1ebd \u0111\u01b0\u1eddng th\u1eb3ng d \u0111i qua A v\u00e0 $\\perp$ v\u1edbi a, v\u1ebd \u0111\u01b0\u1eddng th\u1eb3ng d' \u0111i qua B v\u00e0 $\\perp$ v\u1edbi a. Tr\u00ean \u0111\u01b0\u1eddng th\u1eb3ng d l\u1ea5y \u0111i\u1ec3m D sao cho AD = AB, tr\u00ean \u0111\u01b0\u1eddng th\u1eb3ng d' l\u1ea5y \u0111i\u1ec3m C sao cho hai \u0111i\u1ec3m C v\u00e0 D n\u1eb1m v\u1ec1 c\u00f9ng m\u1ed9t ph\u00eda v\u1edbi \u0111\u01b0\u1eddng th\u1eb3ng a v\u00e0 BC = AB. V\u1ebd c\u00e1c \u0111o\u1ea1n th\u1eb3ng CD, AC, BD. G\u1ecdi O l\u00e0 giao \u0111i\u1ec3m c\u1ee7a AC v\u00e0 BD. <br\/> \u0110o v\u00e0 cho bi\u1ebft s\u1ed1 \u0111o c\u1ee7a c\u00e1c g\u00f3c: $\\widehat{AOD} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} \\\\ \\widehat{BCD} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} \\\\ \\widehat{BOC} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o}$ <\/center>","hint":"","explain":" H\u00ecnh v\u1ebd: <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-37.png' \/><\/center> <br\/><br\/><span class='basic_pink'> \u0110o \u0111\u01b0\u1ee3c: $ \\widehat{AOD} = 90^{o}\\\\ \\widehat{BCD} = 90^{o} \\\\ \\widehat{BOC} = 90^{o} $ <\/span><\/span> "}]}],"id_ques":1384},{"time":14,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"Hai tia ph\u00e2n gi\u00e1c c\u1ee7a hai g\u00f3c k\u1ec1 b\u00f9 th\u00ec vu\u00f4ng g\u00f3c v\u1edbi nhau? ","select":[" \u0110\u00fang "," Sai "],"hint":"T\u00ednh s\u1ed1 \u0111o g\u00f3c t\u1ea1o th\u00e0nh b\u1edfi hai tia ph\u00e2n gi\u00e1c. ","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-22.png' \/><\/center> <span class='basic_left'> Gi\u1ea3 s\u1eed $\\widehat{xOy} $ v\u00e0 $\\widehat{yOx'}$ l\u00e0 hai g\u00f3c k\u1ec1 b\u00f9, <br\/> Ot l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{xOy}$, Ot' l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{x'Oy}$ <br\/> Ta c\u00f3: $\\widehat{xOy} + \\widehat{yOx'} = 180^{o} $ (hai g\u00f3c k\u1ec1 b\u00f9) <br\/> $ \\widehat{yOt} = \\dfrac{1}{2}\\widehat{xOy}, \\widehat{yOt'} = \\dfrac{1}{2}\\widehat{yOx'} $ (tia ph\u00e2n gi\u00e1c) <br\/> $\\Rightarrow \\widehat{tOt'} = \\widehat{yOt} + \\widehat{yOt'} = \\dfrac{1}{2}\\widehat{xOy} + \\dfrac{1}{2}\\widehat{yOx'} = \\dfrac{1}{2}.180^{o} = 90^{o} $ <br\/> $ \\Rightarrow Ot \\perp Ot' $ hay hai tia ph\u00e2n gi\u00e1c c\u1ee7a hai g\u00f3c k\u1ec1 b\u00f9 th\u00ec vu\u00f4ng g\u00f3c v\u1edbi nhau. <\/span> <br\/><br\/><span class='basic_pink'> \u0110\u00e1p \u00e1n l\u00e0 \u0110\u00fang. <\/span><\/span> ","column":2}]}],"id_ques":1385},{"time":14,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":" <span class='basic_left'> Cho $\\widehat{AOB} = 50^{o}.$ G\u1ecdi OC l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{AOB} $. V\u1ebd tia OE l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia OA. V\u1ebd tia OD vu\u00f4ng g\u00f3c v\u1edbi OC (tia OD n\u1eb1m trong g\u00f3c $\\widehat{BOE} $) <br\/> Khi \u0111\u00f3: <\/span>","select":[" A. Tia OD l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{AOE} $ "," B. Tia OD l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{COE} $ ","C. Tia OD l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{BOE} $"],"hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-26.png' \/><\/center> <br\/> <span class='basic_left'> C\u00f3 OC l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{AOB} $ n\u00ean $ \\widehat{COB} = \\dfrac{\\widehat{AOB}}{2} = \\dfrac{50^{o}}{2} = 25^{o} $ <br\/> OD vu\u00f4ng g\u00f3c v\u1edbi OC n\u00ean $\\widehat{COD} = 90^{o} \\\\ \\Rightarrow \\widehat{BOD} = \\widehat{COD} - \\widehat{BOC} \\\\ = 90^{o} - 25^{o} = 65^{o}$ <br\/> OE l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia OA n\u00ean g\u00f3c $ \\widehat{AOE} = 180^{o} \\\\ \\Leftrightarrow \\widehat{AOB} + \\widehat{BOD} + \\widehat{DOE} = 180^{o} \\\\ \\Rightarrow \\widehat{DOE} = 180^{o} - \\widehat{AOB} - \\widehat{BOD} \\\\ = 180^{o} - 50^{o} - 65^{o} \\\\ = 65^{o} $<br\/> Tia OD n\u1eb1m trong g\u00f3c $\\widehat{BOE} $ v\u00e0 $\\widehat{BOD} = \\widehat{DOE} = 65^{o} $ <br\/> Suy ra OD l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{BOE} $ <\/span> <br\/><br\/><span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 C. <\/span><\/span> ","column":1}]}],"id_ques":1386},{"time":14,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"<span class='basic_left'>Cho \u0111o\u1ea1n th\u1eb3ng MN d\u00e0i 6cm. Tr\u00ean tia MN l\u1ea5y \u0111i\u1ec3m P sao cho MP = 1cm, tr\u00ean tia NM l\u1ea5y \u0111i\u1ec3m Q sao cho NQ = 1cm. X\u00e9t c\u00e1c kh\u1eb3ng \u0111\u1ecbnh sau: <br\/> (I) MQ = NP <br\/> (II) Hai \u0111o\u1ea1n th\u1eb3ng MN v\u00e0 PQ c\u00f3 chung \u0111\u01b0\u1eddng trung tr\u1ef1c <br\/> (III) \u0110\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n th\u1eb3ng MN v\u00e0 \u0111\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n th\u1eb3ng PQ tr\u00f9ng nhau <\/span> ","select":["A. Ch\u1ec9 c\u00f3 (I) \u0111\u00fang ","B. Ch\u1ec9 c\u00f3 (I) v\u00e0 (II) \u0111\u00fang ","C. Ch\u1ec9 c\u00f3 (II) v\u00e0 (III) \u0111\u00fang ","D. C\u1ea3 (I), (II) v\u00e0 (III) \u0111\u1ec1u \u0111\u00fang "],"hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/img1.png' \/><\/center> <span class='basic_left'> Ta c\u00f3 MN = 6cm, MP = 1cm, QN = 1cm <br\/> N\u00ean \u0111i\u1ec3m P, Q n\u1eb1m gi\u1eefa hai \u0111i\u1ec3m M v\u00e0 N. <br\/> Suy ra MQ = NP = 5 cm (I \u0111\u00fang) <br\/> G\u1ecdi I l\u00e0 trung \u0111i\u1ec3m c\u1ee7a MN <br\/> $\\Rightarrow $ I c\u0169ng l\u00e0 trung \u0111i\u1ec3m c\u1ee7a PQ <br\/> V\u00ec 4 \u0111i\u1ec3m M, N, P, Q th\u1eb3ng h\u00e0ng (gi\u1ea3 thi\u1ebft) n\u00ean \u0111\u01b0\u1eddng th\u1eb3ng d vu\u00f4ng g\u00f3c v\u1edbi MN t\u1ea1i I v\u1eeba l\u00e0 \u0111\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n th\u1eb3ng MN, v\u1eeba l\u00e0 \u0111\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n th\u1eb3ng PQ. <br\/> $\\Rightarrow$ (II) v\u00e0 (III) \u0111\u00fang <\/span> <br\/><br\/><span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D. <\/span><\/span> ","column":2}]}],"id_ques":1387},{"time":14,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"<span class='basic_left'>Cho g\u00f3c $\\widehat{AOB} = 40^{o}. $ V\u1ebd tia OC l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia OA. T\u00ednh $\\widehat{COD} $ bi\u1ebft r\u1eb1ng: <br\/> OD vu\u00f4ng g\u00f3c v\u1edbi OB, c\u00e1c tia OD v\u00e0 OA thu\u1ed9c hai n\u1eeda m\u1eb7t ph\u1eb3ng \u0111\u1ed1i nhau b\u1edd OB. <\/span> ","select":["A. $130^{o} $ ","B. $140^{o} $ ","C. $50^{o} $ ","D. $60^{o} $ "],"hint":"B\u01b0\u1edbc 1. X\u00e1c \u0111\u1ecbnh \u0111\u00fang v\u1ecb tr\u00ed c\u1ee7a tia OD <br\/> B\u01b0\u1edbc 2. T\u00ednh s\u1ed1 \u0111o g\u00f3c $\\widehat{DOA} $ <br\/> B3. T\u00ednh g\u00f3c $\\widehat{COD} $","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-34.png' \/><\/center> <span class='basic_left'> Ta c\u00f3: OD vu\u00f4ng g\u00f3c v\u1edbi OB (gt)<br\/>$\\Rightarrow$ $\\widehat{DOB}$ = $90^o$<br\/>C\u00e1c tia OD v\u00e0 OA thu\u1ed9c c\u00f9ng m\u1ed9t n\u1eeda m\u1eb7t ph\u1eb3ng \u0111\u1ed1i nhau b\u1edd OB(gt) <br\/> N\u00ean $\\widehat{DOA} = \\widehat{DOB} - \\widehat{AOB} = 90^{o} + 40^{o} = 130^{o}$ <br\/>L\u1ea1i c\u00f3: $\\widehat{DOA}$ v\u00e0 $\\widehat{COD}$ l\u00e0 hai g\u00f3c k\u1ec1 b\u00f9<br\/> Suy ra $ \\widehat{COD} + \\widehat{DOA} = 180^{o}$ <br\/>Hay $ \\widehat{COD} = 180^{o} - \\widehat{DOA} = 180^{o} - 130^{o} = 50^{o}$<br\/>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'>C. <\/span>$50^{o}$<\/span> <br\/> ","column":4}]}],"id_ques":1388},{"time":14,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"<span class='basic_left'>Cho hai g\u00f3c k\u1ec1 b\u00f9 $\\widehat{AOB} $ v\u00e0 $\\widehat{BOC} $ v\u1edbi $\\widehat{AOB} = \\dfrac{1}{2}\\widehat{BOC} $. V\u1ebd tia ph\u00e2n gi\u00e1c OM c\u1ee7a $\\widehat{BOC} $ , v\u1ebd tia ph\u00e2n gi\u00e1c ON c\u1ee7a $\\widehat{MOC} $. Ph\u00e1t bi\u1ec3u n\u00e0o sau \u0111\u00e2y kh\u00f4ng \u0111\u00fang? <\/span> ","select":[" A. $ON \\perp OB $ "," B. Tia OB l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{AOM} $"," C. Hai g\u00f3c $\\widehat{COM} $ v\u00e0 $\\widehat{AOB} $ \u0111\u1ed1i \u0111\u1ec9nh"," D. Hai g\u00f3c $\\widehat{AON} $ v\u00e0 $\\widehat{CON} $ k\u1ec1 b\u00f9 "],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-23.png' \/><\/center><br\/>$\\widehat{AOB} $ v\u00e0 $\\widehat{BOC} $ k\u1ec1 b\u00f9 (gt)<br\/>$\\Rightarrow$ $\\widehat{AOB} $ + $\\widehat{BOC} $ = $180^{o}$<br\/>M\u00e0 $\\widehat{AOB} $ = $\\dfrac{1}{2}\\widehat{BOC} $ n\u00ean $\\widehat{BOC} $ = 2. $\\widehat{AOB} $<br\/>$\\Rightarrow$ $\\widehat{AOB} $ + 2$\\widehat{AOB} $ = $180^{o}$<br\/>3$\\widehat{AOB} $ = $180^{o}$<br\/>$\\widehat{AOB} $ = $60^{o}$ (1)<br\/>$\\widehat{BOC} $ = $180^{o}$ - $60^{o}$ = $120^{o}$<br\/>OM l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a $\\widehat{BOC} $ (gt)<br\/>$\\Rightarrow$ $\\widehat{BOM} $ = $\\widehat{MOC} $ = $\\dfrac{1}{2}\\widehat{BOC} $ = $\\dfrac{1}{2} . 120^{o} $ = $60^{o}$ (2)<br\/>T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $\\widehat{AOB} $ = $\\widehat{BOM} $ = $60^{o}$<br\/>Tia OB n\u1eb1m gi\u1eefa hai tia OA v\u00e0 OM<br\/>$\\Rightarrow$ <b>Tia OB l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a $\\widehat{AOM} $<\/b><br\/>ON l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a $\\widehat{MOC} $ (gt)<br\/> $\\Rightarrow$ $\\widehat{MON} $ = $\\widehat{NOC} $ = $\\dfrac{1}{2}\\widehat{MOC} $ = $\\dfrac{1}{2}.60^{o} $ = $30^{o}$<br\/>$\\widehat{BON} $ = $\\widehat{BOM} $ + $\\widehat{MON} $ = $60^{o} + 30^{o}$ = $90^{o}$<br\/>$\\Rightarrow$ <b> $ON \\perp OB $ <\/b><br\/>$\\widehat{AOB} $ v\u00e0 $\\widehat{BOC} $ k\u1ec1 b\u00f9 (gt)<br\/>$\\Rightarrow$ OA v\u00e0 OC l\u00e0 hai tia \u0111\u1ed1i nhau<br\/>$\\Rightarrow$ <b> $\\widehat{AON} $ v\u00e0 $\\widehat{CON} $ k\u1ec1 b\u00f9 <\/b><br\/>OB v\u00e0 OM kh\u00f4ng ph\u1ea3i l\u00e0 hai tia \u0111\u1ed1i nhau n\u00ean <b> $\\widehat{COM} $ v\u00e0 $\\widehat{AOB} $ kh\u00f4ng \u0111\u1ed1i \u0111\u1ec9nh <\/b><br\/>V\u1eady \u0111\u00e1p \u00e1n sai l\u00e0: <span class='basic_pink'> C. Hai g\u00f3c $\\widehat{COM} $ v\u00e0 $\\widehat{AOB} $ \u0111\u1ed1i \u0111\u1ec9nh<\/span><\/span> <br\/><\/span> ","column":2}]}],"id_ques":1389},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["60"],["24"]]],"list":[{"point":10,"width":50,"type_input":"","ques":"<span class='basic_left'>Cho g\u00f3c vu\u00f4ng $\\widehat{xOy} $, tia Oz n\u1eb1m gi\u1eefa hai tia Ox v\u00e0 Oy sao cho $\\widehat{xOz} = \\dfrac{1}{3}\\widehat{xOy} $ <br\/> S\u1ed1 \u0111o g\u00f3c $\\widehat{yOz}$ l\u00e0: $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o}$ <br\/> V\u1ebd tia Oz' n\u1eb1m gi\u1eefa hai tia Oz v\u00e0 Oy sao cho $\\widehat{z'Oz} = \\dfrac{2}{5}\\widehat{xOy} $ <br\/> S\u1ed1 \u0111o g\u00f3c $\\widehat{z'Oy}$ l\u00e0: $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o}$ <\/span> ","hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai2/lv3/img\/H7C12-15.png' \/><\/center><span class='basic_left'> Theo b\u00e0i ta c\u00f3: $\\widehat{xOy} = 90^{o}$ <br\/> N\u00ean: $\\widehat{xOz} = \\dfrac{1}{3}\\widehat{xOy} = \\dfrac{1}{3}.90^{o} = 30^{o} $ <br\/> Tia Oz n\u1eb1m gi\u1eefa hai tia Ox v\u00e0 Oy n\u00ean $ \\widehat{xOy} = \\widehat{yOz} + \\widehat{xOz} \\\\ \\Rightarrow \\widehat{yOz} = \\widehat{xOy} - \\widehat{xOz} = 90^{o} - 30^{o} = 60^{o} $ <br\/> Ta c\u00f3: $\\widehat{z'Oz} = \\dfrac{2}{5}\\widehat{xOy} = \\dfrac{2}{5}.90^{o} = 36^{o} $ <br\/> Tia Oz' n\u1eb1m gi\u1eefa hai tia Oz v\u00e0 Oy n\u00ean $ \\widehat{yOz} = \\widehat{z'Oy} + \\widehat{z'Oz} \\\\ \\Rightarrow \\widehat{z'Oy} = \\widehat{yOz} - \\widehat{z'Oz} = 60^{o} - 36^{o} = 24^{o} $ <br\/><span class='basic_pink'>\u0110\u00e1p s\u1ed1 l\u00e0 $60^{o}; 24^{o} $<\/span><\/span> <br\/><br\/> "}]}],"id_ques":1390}],"lesson":{"save":0,"level":3}}