{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"Cho hai \u0111\u01b0\u1eddng th\u1eb3ng a, b song song. \u0110i\u1ec3m A $\\in$ a, B $\\in$ b, C $\\in$ b. <br\/> Bi\u1ebft $\\widehat{BAa} = 40^{o}, \\widehat{ACB} = 30^{o} $ nh\u01b0 h\u00ecnh v\u1ebd. <br\/> C\u00e2u n\u00e0o sau \u0111\u00e2y \u0111\u00fang? <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C14-45.png' \/><\/center> ","select":["A. $\\widehat{A_{2}} < \\widehat{B} $","B. $\\widehat{A_{3}} < \\widehat{A_{2}} $","C. $\\widehat{A_{3}} > \\widehat{B} $","D. $\\widehat{A_{3}} = \\widehat{B} $ "],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> N\u1ebfu \u0111\u01b0\u1eddng th\u1eb3ng c c\u1eaft hai \u0111\u01b0\u1eddng th\u1eb3ng song song a v\u00e0 b th\u00ec t\u1ea1o th\u00e0nh c\u00e1c c\u1eb7p g\u00f3c so le trong b\u1eb1ng nhau, c\u1eb7p g\u00f3c \u0111\u1ed3ng v\u1ecb b\u1eb1ng nhau, c\u1eb7p g\u00f3c trong c\u00f9ng ph\u00eda, ngo\u00e0i c\u00f9ng ph\u00eda b\u00f9 nhau. <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> V\u00ec a \/\/ b n\u00ean $ \\widehat{A_{3}} = \\widehat{C} = 30^{o} $ (hai g\u00f3c so le trong) <br\/> C\u00f3 $\\widehat{A_{1}} + \\widehat{A_{2}} + \\widehat{A_{3}} = 180^{o} $<br\/> $ \\Rightarrow \\widehat{A_{2}} $$= 180^{o} - \\widehat{A_{1}} - \\widehat{A_{3}} \\\\ = 180^{o} - 40^{o} - 30^{o} \\\\ = 110^{o} $ <br\/> a \/\/ b n\u00ean $ \\widehat{A_{1}} = \\widehat{B} = 40^{o} $ (hai g\u00f3c so le trong) <br\/> V\u1eady $ \\widehat{A_{2}} > \\widehat{B} \\\\ \\widehat{A_{3}} < \\widehat{A_{2}} \\\\ \\widehat{A_{3}} < \\widehat{B} $ <br\/> <br\/><span class='basic_pink'> \u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span>","column":2}]}],"id_ques":1531},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"Cho tam gi\u00e1c ABC. V\u1ebd $AH \\perp BC (H \\in BC) $. <br\/> Cho bi\u1ebft $\\widehat{ACB} = 30^{o} $. V\u1ebd tia $Ax \\perp AH$. <br\/> Ph\u00e1t bi\u1ec3u n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. Ax, BC song song v\u1edbi nhau v\u00e0 $\\widehat{BAC} =90^{o} $ ","B. $\\widehat{HAC} = 60^{o} $ l\u00e0 g\u00f3c ph\u1ee5 v\u1edbi $\\widehat{CAx} $ ","C. $\\widehat{CAx} = 30^{o} $ l\u00e0 g\u00f3c \u0111\u1ed3ng v\u1ecb v\u1edbi $\\widehat{ACB} $ ","D. $\\widehat{HAC} = 60^{o} $ l\u00e0 g\u00f3c k\u1ec1 b\u00f9 v\u1edbi $\\widehat{CAx} $ "],"hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-46.png' \/><\/center> Tam gi\u00e1c ABC, $AH \\perp BC (H \\in BC) $, $\\widehat{ACB} = 30^{o} $ <br\/> Khi \u0111\u00f3 $\\widehat{HAC} = 60^{o} $ l\u00e0 g\u00f3c ph\u1ee5 v\u1edbi $\\widehat{CAx} $ <br\/> <br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 B. <\/span> ","column":2}]}],"id_ques":1532},{"time":24,"part":[{"time":3,"title":"S\u1eafp x\u1ebfp c\u00e1c c\u00e2u","title_trans":"Tr\u00ean H\u00ecnh 17, cho bi\u1ebft Ax \/\/ Cy. <br\/> H\u00e3y s\u1eafp x\u1ebfp c\u00e1c \u00fd ch\u1ee9ng minh $\\widehat{A} + \\widehat{B} + \\widehat{C} = 360^{o} $","temp":"sequence","correct":[[[1],[4],[5],[3],[2]]],"list":[{"point":10,"image":"https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-17A.png","left":["K\u1ebb tia Bz \/\/ Ax th\u00ec Bz \/\/ Cy","V\u1eady $\\widehat{A} + \\widehat{ABz} + \\widehat{zBC} + \\widehat{C} = 360^{o} $","Hay $\\widehat{A} + \\widehat{B} + \\widehat{C} = 360^{o} $","V\u00e0 $\\widehat{C} + \\widehat{zBC} = 180^{o} $","Do \u0111\u00f3 $\\widehat{A} + \\widehat{ABz} = 180^{o} $ "],"top":55,"hint":"","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-17B.png' \/><\/center> K\u1ebb tia Bz \/\/ Ax th\u00ec Bz \/\/ Cy <br\/> Do \u0111\u00f3 $\\widehat{A} + \\widehat{ABz} = 180^{o} $ (hai g\u00f3c trong c\u00f9ng ph\u00eda) <br\/> V\u00e0 $\\widehat{C} + \\widehat{zBC} = 180^{o} $ (hai g\u00f3c trong c\u00f9ng ph\u00eda) <br\/> V\u1eady $\\widehat{A} + \\widehat{ABz} + \\widehat{zBC} + \\widehat{C} = 180^{o} + 180^{o} = 360^{o} $ <br\/> hay $\\widehat{A} + \\widehat{B} + \\widehat{C} = 360^{o} $ "}]}],"id_ques":1533},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["30"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" Cho h\u00ecnh v\u1ebd. <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-44.png' \/><\/center> <br\/> S\u1ed1 \u0111o g\u00f3c x 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/bai7/lv3/img\/H7C17-44B.png' \/><\/center> <span class='basic_left'> Ta c\u00f3 $a \\perp c, b \\perp c $ n\u00ean a \/\/ b. <br\/> Trong g\u00f3c $\\widehat{DEC} $ k\u1ebb tia Et \/\/ a $\\Rightarrow $ Et \/\/ b. <br\/> C\u00f3 Et \/\/ b n\u00ean $\\widehat{E_{1}} = \\widehat{C} = 40^{o} $ (so le trong) <br\/> C\u00f3 $ \\widehat{DEC} = \\widehat{E_{1}} + \\widehat{E_{2}} \\\\ \\Rightarrow \\widehat{E_{2}} = \\widehat{DEC} - \\widehat{E_{1}} = 70^{o} - 40^{o} = 30^{o} $ <br\/> V\u00ec Et \/\/ a n\u00ean $x = \\widehat{E_{2}} = 30^{o} $ (so le trong) <\/span> <br\/> <br\/> <span class='basic_pink'> V\u1eady $x = 30^{o} $ <\/span><\/span> <br\/>"}]}],"id_ques":1534},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["43"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" <span class='basic_left'>Cho c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng MN, PQ, CD sao cho MN \/\/ PQ v\u00e0 CD c\u1eaft MN, PQ t\u1ea1i A v\u00e0 B. Bi\u1ebft $\\widehat{ABP} = 47^{o} $ <br\/>T\u1eeb A k\u1ebb $AH \\perp PQ$. <br\/> S\u1ed1 \u0111o g\u00f3c $\\widehat{HAB} $ 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/bai7/lv3/img\/H7C17-50.png' \/><\/center> <span class='basic_left'> Ta c\u00f3 MN \/\/ PQ n\u00ean $\\widehat{NAB} = \\widehat{ABP} = 47^{o} $ (so le trong) <br\/>C\u00f3 $AH \\perp PQ$ m\u00e0 PQ \/\/ MN n\u00ean $AH \\perp MN$ <br\/> Suy ra $\\widehat{NAH} = 90^{o} $ <br\/> C\u00f3 $\\widehat{NAH} = \\widehat{HAB} + \\widehat{NAB} \\\\ \\Rightarrow \\widehat{HAB} = \\widehat{NAH} - \\widehat{NAB} = 90^{o} - 47^{o} = 43^{o}$ <\/span> <br\/> <br\/> <span class='basic_pink'> V\u1eady $\\widehat{HAB} = 43^{o} $ <\/span><\/span> <br\/>"}]}],"id_ques":1535},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["10"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" Cho h\u00ecnh v\u1ebd. Tia $At \\perp AB$ <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-41.png' \/><\/center> T\u00ednh s\u1ed1 \u0111o $\\widehat{BAy} - \\widehat{tCx'} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} $","hint":"","explain":" <span class='basic_left'> Ta c\u00f3 $At \\perp AB \\Rightarrow \\widehat{BAC} = 90^{o} $ <br\/> Theo b\u00e0i $xx' \\perp zz', yy' \\perp zz' $ n\u00ean xx' \/\/ yy' <br\/> V\u00ec xx' \/\/ yy' n\u00ean $\\widehat{xBA} + \\widehat{BAy} = 180^{o} $ (hai g\u00f3c trong c\u00f9ng ph\u00eda) <br\/> Suy ra $\\widehat{BAy} = 180^{o} - \\widehat{xBA} \\\\ = 180^{o} - 130^{o} \\\\ = 50^{o} $ <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $ \\widehat{BAy} + \\widehat{BAC} + \\widehat{CAy'} = 180^{o} $ <br\/> Suy ra $ \\widehat{CAy'} = 180^{o} - \\widehat{BAy} - \\widehat{BAC} \\\\ = 180^{o} - 50^{o} - 90^{o} = 40^{o} $ <br\/> V\u00ec xx' \/\/ yy' n\u00ean $\\widehat{tCx'} = \\widehat{CAy'} = 40^{o} $ (c\u1eb7p g\u00f3c \u0111\u1ed3ng v\u1ecb) <br\/> V\u1eady $\\widehat{BAy} - \\widehat{tCx'} = 50^{o} - 40^{o} = 10^{o} $<\/span> <br\/> <br\/> <span class='basic_pink'> V\u1eady $\\widehat{BAy} - \\widehat{tCx'} = 10^{o} $ <\/span><\/span> <br\/>"}]}],"id_ques":1536},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["100"],["80"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" Cho hai g\u00f3c c\u00f3 \u0111\u1ec9nh A v\u00e0 B v\u00e0 c\u00e1c c\u1ea1nh t\u01b0\u01a1ng \u1ee9ng song song. <br\/> T\u00ecm s\u1ed1 \u0111o m\u1ed7i g\u00f3c, bi\u1ebft $4\\widehat{A} = 5\\widehat{B} $ <br\/>\u0110\u00e1p \u00e1n: $\\widehat{A} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} \\\\ \\widehat{B} = \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} $","hint":"","explain":" <span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-51.png' \/><\/center> Ta bi\u1ebft r\u1eb1ng hai g\u00f3c c\u00f3 c\u1ea1nh t\u01b0\u01a1ng \u1ee9ng song song th\u00ec b\u1eb1ng nhau ho\u1eb7c b\u00f9 nhau, <br\/> m\u00e0 $\\widehat{A} \\neq \\widehat{B} $ n\u00ean $\\widehat{A} + \\widehat{B} = 180^{o} $ <br\/> Theo \u0111\u1ec1 b\u00e0i, $4\\widehat{A} = 5\\widehat{B}$ n\u00ean $\\widehat{A} = \\dfrac{5}{4}\\widehat{B} $ <br\/> suy ra $\\dfrac{5}{4}\\widehat{B} + \\widehat{B} = 180^{o} \\\\ \\dfrac{9}{4}\\widehat{B} = 180^{o} \\\\ \\Leftrightarrow \\widehat{B} = 80^{o} $ <br\/>M\u00e0 $\\widehat{A} + \\widehat{B} = 180^{o} $<br\/>N\u00ean $\\widehat{A} = 180^{o} - \\widehat{B} = 180^{o} - 80^{o} = 100^{o}$ <br\/> <span class='basic_pink'> V\u1eady $\\widehat{B} = 80^{o} \\\\ \\widehat{A} = 100^{o}$ <\/span><\/span> <br\/><\/span>"}]}],"id_ques":1537},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["t","t","f","t"]],"list":[{"point":10,"ques":"Cho $\\widehat{xOy} = 70^{o} $. Tr\u00ean Ox l\u1ea5y \u0111i\u1ec3m A. K\u1ebb tia Az sao cho $\\widehat{xAz} = 70^{o} $. Tr\u00ean tia Az l\u1ea5y \u0111i\u1ec3m B. <br\/> K\u1ebb tia Bt c\u1eaft Oy t\u1ea1i C sao cho $\\widehat{CBz} = 110^{o} $. K\u1ebb $AH \\perp Oy $ v\u00e0 $ CK \\perp Az$","image":"","col_name":["","\u0110\u00fang","Sai"],"arr_ques":["Az \/\/ Oy","Ox \/\/ Bt ","$\\widehat{BCO} = 70^{o} $","AH \/\/ CK "],"hint":"","explain":["<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-21.png' \/><\/center> <br\/> \u0110\u00fang. V\u00ec c\u00f3 hai g\u00f3c \u0111\u1ed3ng v\u1ecb $\\widehat{xAz} = \\widehat{xOy} (= 70^{o} ) $ ","<br\/> \u0110\u00fang. V\u00ec $\\widehat{ABC} + \\widehat{CBz} = 180^{o}$ (hai g\u00f3c k\u1ec1 b\u00f9)<br\/>Suy ra $\\widehat{ABC} = 180^{o} - \\widehat{CBz} = 180^{o} - 110^{o} = 70^{o}$. M\u00e0 $\\widehat{xAz} = 70^{o}$. N\u00ean $\\widehat{ABC} = \\widehat{xAz}$<br\/>L\u1ea1i c\u00f3: $\\widehat{ABC}$ v\u00e0 $\\widehat{xAz}$ \u1edf v\u1ecb tr\u00ed so le trong<br\/>Suy ra Ox \/\/ Bt ","<br\/>Sai. V\u00ec Az \/\/ Oy (ch\u1ee9ng minh tr\u00ean) suy ra $\\widehat{BCO} = \\widehat{CBz} = 110^{o} $ ","<br\/> \u0110\u00fang. V\u00ec Az \/\/ Oy (ch\u1ee9ng minh tr\u00ean), m\u00e0 $ CK \\perp Az$ (gi\u1ea3 thi\u1ebft)<br\/>Suy ra $ CK \\perp Oy$ (quan h\u1ec7 gi\u1eefa t\u00ednh vu\u00f4ng g\u00f3c v\u1edbi t\u00ednh song song)<br\/>L\u1ea1i c\u00f3: $AH \\perp Oy $ (gi\u1ea3 thi\u1ebft)<br\/>Suy ra AH \/\/ BK "]}]}],"id_ques":1538},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"Cho h\u00ecnh v\u1ebd, bi\u1ebft xx' \/\/ yy' v\u00e0 t\u1ec9 s\u1ed1 \u0111o c\u1ee7a $\\widehat{xAB} $ v\u00e0 $\\widehat{ABy} $ l\u00e0 2 : 3 <br\/> Khi \u0111\u00f3 t\u1ed5ng s\u1ed1 \u0111o c\u1ee7a hai g\u00f3c $\\widehat{zAx'}$ v\u00e0 $\\widehat{zBy'} $ l\u00e0: <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-14.png' \/><\/center> ","select":["A. $36^{o}$ ","B. $72^{o}$ ","C. $108^{o}$ ","D. $144^{o}$"],"hint":"","explain":" <span class='basic_left'> Ta c\u00f3 xx' \/\/ yy' n\u00ean $\\widehat{xAB} + \\widehat{ABy} = 180^{o} $ (hai g\u00f3c trong c\u00f9ng ph\u00eda) <br\/> M\u00e0 theo gi\u1ea3 thi\u1ebft c\u00f3: $\\dfrac{\\widehat{xAB}}{2} = \\dfrac{\\widehat{ABy}}{3} $ <br\/> \u00c1p d\u1ee5ng t\u00ednh ch\u1ea5t d\u00e3y t\u1ec9 s\u1ed1 b\u1eb1ng nhau ta \u0111\u01b0\u1ee3c: <br\/> $ \\dfrac{\\widehat{xAB}}{2} = \\dfrac{\\widehat{ABy}}{3} = \\dfrac{\\widehat{xAB} +\\widehat{ABy}}{2+3} = \\dfrac{180^{o}}{5} = 36^{o} \\\\ \\Rightarrow \\widehat{xAB} = 2.36^{o} = 72^{o} $ <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $\\widehat{xAB} = \\widehat{zAx'} $ (hai g\u00f3c \u0111\u1ed1i \u0111\u1ec9nh ) <br\/> $\\Rightarrow \\widehat{zAx'} = 72^{o} $ <br\/> V\u00ec xx' \/\/ yy' n\u00ean $\\widehat{zAx'} = \\widehat{zBy'} $ (hai g\u00f3c \u0111\u1ed3ng v\u1ecb) <br\/> Suy ra $ \\widehat{zAx'} + \\widehat{zBy'} = 2 \\widehat{zAx'} = 2.72^{o} = 144^{o} $<\/span> <br\/> <br\/> <span class='basic_pink'>\u0110\u00e1p \u00e1n \u0111\u00fang l\u00e0 D. <\/span> ","column":4}]}],"id_ques":1539},{"time":24,"part":[{"title":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["140"],["70"]]],"list":[{"point":10,"width":40,"content":"","type_input":"","ques":" <span class='basic_left'> Cho g\u00f3c xOy. Tia Oz l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{xOy} $. G\u1ecdi Ot l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia Ox, Oh l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia Oz. Cho bi\u1ebft $\\widehat{xOy} + \\widehat{tOh} = 210^{o} $<br\/> S\u1ed1 \u0111o g\u00f3c $\\widehat{xOy} $ l\u00e0: $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} $ <br\/> S\u1ed1 \u0111o g\u00f3c $\\widehat{tOh} $ l\u00e0: $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^{o} $ ","hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai7/lv3/img\/H7C17-04.png' \/><\/center> Ta c\u00f3 Ot l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia Ox, Oh l\u00e0 tia \u0111\u1ed1i c\u1ee7a tia Oz <br\/> n\u00ean $\\widehat{tOh} = \\widehat{xOz} $ (hai g\u00f3c \u0111\u1ed1i \u0111\u1ec9nh) <br\/> M\u1eb7t kh\u00e1c Oz l\u00e0 tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{xOy} $ n\u00ean $\\widehat{xOy} = 2\\widehat{xOz} = 2\\widehat{tOh} $ <br\/> Theo \u0111\u1ec1 b\u00e0i c\u00f3: $\\widehat{xOy} + \\widehat{tOh} = 210^{o} \\\\ \\Leftrightarrow 2\\widehat{tOh} + \\widehat{tOh} = 210^{o} \\\\ \\Leftrightarrow 3\\widehat{tOh} = 210^{o} \\\\ \\Leftrightarrow \\widehat{tOh} = 70^{o} $ <br\/> Suy ra $\\widehat{xOy} = 2\\widehat{tOh} = 2.70^{o} = 140^{o} $ <br\/> <br\/> <span class='basic_pink'>V\u1eady $ \\widehat{xOy} = 140^{o} \\\\ \\widehat{tOh} = 70^{o} $ <\/span><\/span> <br\/>"}]}],"id_ques":1540}],"lesson":{"save":0,"level":3}}