{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"fill_the_blank_random","correct":[[["60"],["120"]]],"list":[{"point":10,"width":40,"type_input":"","ques":"<span class='basic_left'> Cho h\u00ecnh thang c\u00e2n $ABCD$, \u0111\u00e1y nh\u1ecf $CD$, t\u1ed5ng hai g\u00f3c $A$ v\u00e0 $B$ b\u1eb1ng m\u1ed9t n\u1eeda t\u1ed5ng hai g\u00f3c $C$ v\u00e0 $D$. \u0110\u01b0\u1eddng ch\u00e9o $AC$ vu\u00f4ng g\u00f3c v\u1edbi c\u1ea1nh b\u00ean $BC$. <br\/> <b> C\u00e2u 1: <\/b> T\u00ednh s\u1ed1 \u0111o hai g\u00f3c k\u1ec1 c\u1ea1nh b\u00ean c\u1ee7a h\u00ecnh thang c\u00e2n. <br\/><br\/> <b> \u0110\u00e1p \u00e1n: <\/b> $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^o$ v\u00e0 $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^o$ <\/span> ","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_1.jpg' \/><\/center> Ta c\u00f3: <br\/> $\\begin{align} & \\widehat{A}+\\widehat{B}=\\dfrac{1}{2}\\left( \\widehat{C}+\\widehat{D} \\right) \\\\ & \\Rightarrow \\widehat{C}+\\widehat{D}=2\\left( \\widehat{A}+\\widehat{B} \\right) \\\\ \\end{align}$ <br\/> M\u00e0: $\\widehat{A}=\\widehat{B};\\,\\,\\widehat{C}=\\widehat{D}$ <br\/> $\\begin{align} & \\Rightarrow 2\\widehat{C}=4\\widehat{B} \\\\ & \\Rightarrow \\widehat{C}=2\\widehat{B}\\,\\,\\,\\left( 1 \\right) \\\\ \\end{align}$ <br\/> M\u1eb7t kh\u00e1c: $\\widehat{B}+\\widehat{C}={{180}^{o}}$ (t\u00ednh ch\u1ea5t h\u00ecnh thang) (2)<br\/> T\u1eeb (1) v\u00e0 (2) suy ra: <br\/> $\\begin{align} & \\widehat{B}={{180}^{o}}:3={{60}^{o}} \\\\ & \\Rightarrow \\widehat{C}=2\\widehat{B}={{2.60}^{o}}={{120}^{o}} \\\\ \\end{align}$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $60$ v\u00e0 $120$. <\/span> <\/span> "}]}],"id_ques":1541},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"fill_the_blank","correct":[[["5a"]]],"list":[{"point":10,"width":40,"type_input":"","ques":"<span class='basic_left'> Cho h\u00ecnh thang c\u00e2n $ABCD$, \u0111\u00e1y nh\u1ecf $CD$, t\u1ed5ng hai g\u00f3c $A$ v\u00e0 $B$ b\u1eb1ng m\u1ed9t n\u1eeda t\u1ed5ng hai g\u00f3c $C$ v\u00e0 $D$. \u0110\u01b0\u1eddng ch\u00e9o $AC$ vu\u00f4ng g\u00f3c v\u1edbi c\u1ea1nh b\u00ean $BC$. <br\/> <b> C\u00e2u 2: <\/b> Cho $CD=a$. T\u00ednh chu vi c\u1ee7a h\u00ecnh thang c\u00e2n $ABCD$ theo $a$. <br\/><br\/> <b> \u0110\u00e1p \u00e1n: <\/b> $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ <\/span> ","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_1.jpg' \/><\/center> Theo c\u00e2u 1, ta t\u00ednh \u0111\u01b0\u1ee3c: $\\widehat{B}=60^o$ <br\/> X\u00e9t trong tam gi\u00e1c $ABC$ c\u00f3: $\\widehat{CAB}=30^o; \\widehat{ABC}=60^o$ <br\/> $\\Rightarrow AB=2BC$ <br\/> Do $\\widehat{CAB}=30^o \\Rightarrow \\widehat{CAD}=30^o$ <br\/> Do $\\widehat{ACB}=90^o \\Rightarrow \\widehat{ACD}=30^o$ <br\/> Suy ra $\\Delta ADC$ c\u00e2n t\u1ea1i $D$. <br\/> $\\Rightarrow AD=DC=a \\Rightarrow AD=BC=a$ (t\u00ednh ch\u1ea5t h\u00ecnh thang c\u00e2n). <br\/> Do v\u1eady: $AB=2BC=2a$ <br\/> Chu vi c\u1ee7a h\u00ecnh thang c\u00e2n $ABCD$ l\u00e0: <br\/> $AB+CD+BC+DA$$=2a+a+a+a=5a$. <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $5a$. <\/span> <\/span> "}]}],"id_ques":1542},{"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":" <span class='basic_left'> H\u00ecnh ch\u1eef nh\u1eadt c\u00f3 chu vi l\u00e0 $84\\, cm$. Kho\u1ea3ng c\u00e1ch t\u1eeb giao \u0111i\u1ec3m c\u1ee7a \u0111\u01b0\u1eddng ch\u00e9o \u0111\u1ebfn c\u1ea1nh nh\u1ecf l\u1edbn h\u01a1n kho\u1ea3ng c\u00e1ch t\u1eeb giao \u0111i\u1ec3m \u0111\u00f3 \u0111\u1ebfn c\u1ea1nh l\u1edbn h\u01a1n l\u00e0 $6\\, cm$. \u0110\u1ed9 d\u00e0i hai c\u1ea1nh k\u1ec1 c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt l\u00e0: <\/span>","select":[" A. $5\\, cm$ v\u00e0 $26\\, cm$"," B. $15\\, cm$ v\u00e0 $27\\, cm$","C. $14\\, cm$ v\u00e0 $30\\, cm$","D. $13\\, cm$ v\u00e0 $29\\, cm$"],"hint":"G\u1ecdi kho\u1ea3ng c\u00e1ch t\u1eeb giao \u0111i\u1ec3m hai \u0111\u01b0\u1eddng ch\u00e9o t\u1edbi c\u1ea1nh nh\u1ecf h\u01a1n l\u00e0 $a\\, cm$, t\u1edbi c\u1ea1nh l\u1edbn h\u01a1n l\u00e0 $b\\, cm$ $(a > b)$. <br\/> T\u00ecm t\u1ed5ng v\u00e0 hi\u1ec7u c\u1ee7a $a$ v\u00e0 $b$, t\u1eeb \u0111\u00f3 t\u00ednh ra $2a$ v\u00e0 $2b$.","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_2.jpg' \/><\/center> G\u1ecdi kho\u1ea3ng c\u00e1ch t\u1eeb giao \u0111i\u1ec3m hai \u0111\u01b0\u1eddng ch\u00e9o t\u1edbi c\u1ea1nh nh\u1ecf h\u01a1n l\u00e0 $a\\, (cm)$, t\u1edbi c\u1ea1nh l\u1edbn h\u01a1n l\u00e0 $b\\, (cm)$ $(a > b)$. <br\/> \u0110\u1ed9 d\u00e0i hai c\u1ea1nh k\u1ec1 c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt theo $a, b$ l\u1ea7n l\u01b0\u1ee3t l\u00e0: $2a\\, (cm)$ v\u00e0 $2b\\, (cm)$ <br\/> Theo b\u00e0i, ta c\u00f3: <br\/> $\\begin{aligned} & \\left\\{ \\begin{aligned} & a-b=6 \\\\ & 4(a+b)=84 \\\\ \\end{aligned} \\right. \\\\ & \\Rightarrow \\left\\{ \\begin{aligned} & a-b=6 \\\\ & a+b=21 \\\\ \\end{aligned} \\right. \\\\ & \\Rightarrow \\left\\{ \\begin{aligned} & 2a=27 \\\\ & 2b=15 \\\\ \\end{aligned} \\right. \\\\ \\end{aligned}$ <br\/> \u0110\u1ed9 d\u00e0i hai c\u1ea1nh k\u1ec1 c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt l\u00e0: $15\\, cm$ v\u00e0 $27\\, cm$ <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B. <\/span><\/span> ","column":2}]}],"id_ques":1543},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"fill_the_blank","correct":[[["150"]]],"list":[{"point":10,"width":40,"type_input":"","ques":"<span class='basic_left'> Cho g\u00f3c nh\u1ecdn $\\widehat{xOy}=75^o$. Cho \u0111i\u1ec3m $M$ thu\u1ed9c mi\u1ec1n trong c\u1ee7a g\u00f3c $xOy$ sao cho $\\widehat{MOx}=60^o$. K\u1ebb $ME\\bot Ox; MF\\bot Oy$. \u0110i\u1ec3m $A$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $OM$. Tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat {EAF}$ c\u1eaft $EF$ \u1edf $H$. <br\/><br\/> <b> C\u00e2u 1:<\/b> T\u00ednh $\\widehat{EAF}$. <br\/><br\/> <b> \u0110\u00e1p \u00e1n: <\/b> $\\widehat{EAF}=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^o$ <\/span> ","Hint":" $\\widehat{EAF}=\\widehat{EAM}+\\widehat{MAF}$","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_4.jpg' \/><\/center> X\u00e9t t\u1ee9 gi\u00e1c $OEMF$ c\u00f3: <br\/> $\\widehat{EOF}+\\widehat{OEM}+\\widehat{EMF}+\\widehat{OFM}=360^o$ <br\/> $\\widehat{EMF}=360^o- (\\widehat{EOF}+\\widehat{OEM}+\\widehat{OFM})$<br\/> $\\widehat{EMF}=360^o-(75^o+90^o+90^o)$ <br\/> $\\widehat{EMF}=105^o$ <br\/> Do $\\Delta OMF$ vu\u00f4ng t\u1ea1i $F$ v\u00e0 $OA=MA$ n\u00ean $OA=AF$ <br\/> $\\Rightarrow \\Delta OAF$ c\u00e2n t\u1ea1i $A$ <br\/> $\\Rightarrow \\widehat{F_1}=\\widehat{O_2}$ <br\/> Theo gi\u1ea3 thi\u1ebft: $\\widehat{MOx}=\\widehat{O_1}=60^o \\Rightarrow \\widehat{MOy}=\\widehat{O_2}=15^o$ <br\/> X\u00e9t trong $\\Delta OAF$ c\u00f3 $\\widehat{MAF}$ l\u00e0 g\u00f3c ngo\u00e0i \u0111\u1ec9nh $A$ n\u00ean: <br\/> $\\widehat{MAF} =2\\widehat{O_2}=30^o$ (1) <br\/> T\u01b0\u01a1ng t\u1ef1, ta ch\u1ee9ng minh \u0111\u01b0\u1ee3c $\\Delta OAE$ c\u00e2n t\u1ea1i $A$. <br\/> $\\Rightarrow \\widehat{O_1}=\\widehat{E_1}$ <br\/> X\u00e9t $\\Delta OAE$ c\u00f3 $\\widehat{EAM}$ l\u00e0 g\u00f3c ngo\u00e0i \u0111\u1ec9nh $A$ n\u00ean: <br\/> $\\widehat{EAM}=2\\widehat{O_1}=120^o$ (2) <br\/> T\u1eeb (1) v\u00e0 (2): $\\widehat{EAF}=\\widehat{EAM}+\\widehat{MAF}$$=120^o+30^o=150^o$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $150$. <\/span> <\/span> "}]}],"id_ques":1544},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang ho\u1eb7c sai","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":" <span class='basic_left'> Cho g\u00f3c nh\u1ecdn $\\widehat{xOy}=75^o$. Cho \u0111i\u1ec3m $M$ thu\u1ed9c mi\u1ec1n trong c\u1ee7a g\u00f3c $xOy$ sao cho $\\widehat{MOx}=60^o$. K\u1ebb $ME\\bot Ox; MF\\bot Oy$. \u0110i\u1ec3m $A$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $OM$. Tia ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat {EAF}$ c\u1eaft $EF$ \u1edf $H$. <br\/><br\/> <b> C\u00e2u 2:<\/b> Ta ch\u1ee9ng minh \u0111\u01b0\u1ee3c $AH\\bot EF$. <\/span>","select":[" \u0110\u00fang"," Sai"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_4.jpg' \/><\/center> Theo c\u00e2u 1, ta \u0111\u00e3 ch\u1ec9 ra \u0111\u01b0\u1ee3c: $AE=AF=OA$ <br\/> $\\Rightarrow \\Delta EAF$ c\u00e2n t\u1ea1i $A$. <br\/> M\u00e0 theo gi\u1ea3 thi\u1ebft, $AH$ l\u00e0 ph\u00e2n gi\u00e1c c\u1ee7a g\u00f3c $\\widehat{EAF}$ n\u00ean c\u0169ng l\u00e0 \u0111\u01b0\u1eddng cao t\u1eeb \u0111\u1ec9nh $A$ trong $\\Delta EAF$ <br\/> $\\Rightarrow AH \\bot EF$. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang. <\/span><\/span> ","column":2}]}],"id_ques":1545},{"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":" <span class='basic_left'> Trong h\u00ecnh thoi $ABCD$, \u0111\u01b0\u1eddng cao xu\u1ea5t ph\u00e1t t\u1eeb \u0111\u1ec9nh g\u00f3c t\u00f9 $A$ chia c\u1ea1nh $BC$ th\u00e0nh hai \u0111o\u1ea1n b\u1eb1ng nhau. S\u1ed1 \u0111o c\u00e1c g\u00f3c k\u1ec1 v\u1edbi m\u1ed7i c\u1ea1nh h\u00ecnh thoi l\u00e0: <\/span>","select":[" A. $30^o$ v\u00e0 $150^o$"," B. $40^o$ v\u00e0 $140^o$","C. $50^o$ v\u00e0 $130^o$","D. $60^o$ v\u00e0 $120^o$"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_3.jpg' \/><\/center> Theo gi\u1ea3 thi\u1ebft, $\\Delta ABC$ c\u00f3 ph\u00e2n gi\u00e1c g\u00f3c $A$ \u0111\u1ed3ng th\u1eddi l\u00e0 trung tuy\u1ebfn. <br\/> $\\Rightarrow \\Delta ABC$ c\u00e2n t\u1ea1i $A$. <br\/> M\u00e0 $AB=BC$ ($ABCD$ l\u00e0 h\u00ecnh thoi) n\u00ean $\\Delta ABC$ \u0111\u1ec1u. <br\/> $\\Rightarrow \\widehat{B}=60^o$ <br\/> M\u1eb7t kh\u00e1c: $\\widehat{A}+\\widehat{B}=180^o$ (t\u00ednh ch\u1ea5t h\u00ecnh thoi). <br\/> $\\Rightarrow \\widehat{A}=180^o-60^o$ <br\/> $\\Rightarrow \\widehat{A}=120^o$ <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D. <\/span><\/span> ","column":2}]}],"id_ques":1546},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"\u0110\u1ec1 chung cho b\u1ed1n c\u00e2u","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":" <span class='basic_left'> Cho $\\Delta ABC$ v\u00e0 \u0111i\u1ec3m $H$ thu\u1ed9c mi\u1ec1n trong c\u1ee7a tam gi\u00e1c. G\u1ecdi $M, N, P, Q$ theo th\u1ee9 t\u1ef1 l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u00e1c \u0111o\u1ea1n th\u1eb3ng $HB, HC, AC, AB$. <br\/><br\/> <b> C\u00e2u 1:<\/b> T\u1ee9 gi\u00e1c $MNPQ$ l\u00e0 h\u00ecnh g\u00ec? <\/span>","select":[" A. H\u00ecnh b\u00ecnh h\u00e0nh"," B. H\u00ecnh ch\u1eef nh\u1eadt","C. H\u00ecnh thoi","D. H\u00ecnh vu\u00f4ng"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_5.jpg' \/><\/center> X\u00e9t $\\Delta ABC$ c\u00f3: $AQ=BQ; AP=CP$ n\u00ean $PQ \/\/BC$ v\u00e0 $PQ=\\dfrac{1}{2}BC$ (1) <br\/> Trong $\\Delta HBC$ c\u00f3: $MH=MB; HN=NC$ (gi\u1ea3 thi\u1ebft) <br\/> $\\Rightarrow MN \/\/BC$ v\u00e0 $MN= \\dfrac{1}{2}BC$ (2) <br\/> T\u1eeb (1) v\u00e0 (2) suy ra: $PQ \/\/MN$ v\u00e0 $PQ=MN$ <br\/> $\\Rightarrow MNPQ$ l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh (d\u1ea5u hi\u1ec7u nh\u1eadn bi\u1ebft) <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0: A <\/span><\/span> ","column":2}]}],"id_ques":1547},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"\u0110\u1ec1 chung cho b\u1ed1n c\u00e2u","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":" <span class='basic_left'> Cho $\\Delta ABC$ v\u00e0 \u0111i\u1ec3m $H$ thu\u1ed9c mi\u1ec1n trong c\u1ee7a tam gi\u00e1c. G\u1ecdi $M, N, P, Q$ theo th\u1ee9 t\u1ef1 l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u00e1c \u0111o\u1ea1n th\u1eb3ng $HB, HC, AC, AB$. <br\/><br\/> <b> C\u00e2u 2:<\/b> \u0110\u1ec3 $MNPQ$ l\u00e0 h\u00ecnh ch\u1eef nh\u1eadt th\u00ec \u0111i\u1ec3m $H$ ch\u1ea1y tr\u00ean: <\/span>","select":[" A. \u0110\u01b0\u1eddng trung tuy\u1ebfn t\u1eeb \u0111\u1ec9nh $A$ c\u1ee7a $\\Delta ABC$ "," B. \u0110\u01b0\u1eddng trung tuy\u1ebfn t\u1eeb \u0111\u1ec9nh $B$ c\u1ee7a $\\Delta ABC$","C. \u0110\u01b0\u1eddng cao t\u1eeb \u0111\u1ec9nh $A$ c\u1ee7a $\\Delta ABC$","D. \u0110\u01b0\u1eddng cao t\u1eeb \u0111\u1ec9nh $B$ c\u1ee7a $\\Delta ABC$"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_5b.jpg' \/><\/center> Theo c\u00e2u 1, ta ch\u1ee9ng minh \u0111\u01b0\u1ee3c $MNPQ$ l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh <br\/> \u0110\u1ec3 $MNPQ$ l\u00e0 h\u00ecnh ch\u1eef nh\u1eadt th\u00ec h\u00ecnh b\u00ecnh h\u00e0nh $MNPQ$ c\u00f3 m\u1ed9t g\u00f3c vu\u00f4ng. <br\/> Gi\u1ea3 s\u1eed: $\\widehat{QPN}=90^o$ <br\/> Ta d\u1ec5 d\u00e0ng ch\u1ec9 ra \u0111\u01b0\u1ee3c: $PN \/\/AH$ <br\/> M\u00e0: $PQ \/\/BC$ (theo c\u00e2u 1) <br\/> Do \u0111\u00f3 \u0111\u1ec3 $\\widehat{QPN}=90^o$ th\u00ec $AH \\bot BC$. <br\/> \u0110i\u1ec3m $H$ thu\u1ed9c \u0111\u01b0\u1eddng cao h\u1ea1 t\u1eeb $A$ c\u1ee7a tam gi\u00e1c $ABC$ v\u00e0 thu\u1ed9c mi\u1ec1n trong c\u1ee7a tam gi\u00e1c khi g\u00f3c $B$ l\u00e0 g\u00f3c nh\u1ecdn. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C. <\/span><\/span> ","column":2}]}],"id_ques":1548},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang ho\u1eb7c sai","title_trans":"\u0110\u1ec1 chung cho b\u1ed1n c\u00e2u","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":" <span class='basic_left'> Cho $\\Delta ABC$ v\u00e0 \u0111i\u1ec3m $H$ thu\u1ed9c mi\u1ec1n trong c\u1ee7a tam gi\u00e1c. G\u1ecdi $M, N, P, Q$ theo th\u1ee9 t\u1ef1 l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u00e1c \u0111o\u1ea1n th\u1eb3ng $HB, HC, AC, AB$. <br\/><br\/> <b> C\u00e2u 3:<\/b> \u0110i\u1ec3m $H$ ch\u1ea1y tr\u00ean c\u00f9ng tr\u00f2n thu\u1ed9c \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $A$, b\u00e1n k\u00ednh $BC$ (ph\u1ea7n cung tr\u00f2n thu\u1ed9c mi\u1ec1n trong $\\Delta ABC$) th\u00ec $MNPQ$ l\u00e0 h\u00ecnh thoi. <\/span>","select":[" \u0110\u00fang "," Sai"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_5.jpg' \/><\/center> Theo c\u00e2u 1, ta ch\u1ee9ng minh \u0111\u01b0\u1ee3c $MNPQ$ l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh. <br\/> \u0110\u1ec3 $MNPQ$ l\u00e0 h\u00ecnh thoi th\u00ec $MN=MQ$ <br\/> M\u00e0 theo c\u00e2u 1, ta ch\u1ec9 ra \u0111\u01b0\u1ee3c: $MN=\\dfrac{1}{2}BC$ v\u00e0 $MQ=\\dfrac{1}{2}AH$ <br\/> Do \u0111\u00f3, \u0111\u1ec3 $MN=MQ$ th\u00ec $AH=BC$ <br\/> V\u1eady \u0111i\u1ec3m $H$ ch\u1ea1y tr\u00ean cung tr\u00f2n thu\u1ed9c \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $A$, b\u00e1n k\u00ednh $BC$ (ph\u1ea7n cung tr\u00f2n thu\u1ed9c mi\u1ec1n trong $\\Delta ABC$) th\u00ec $MNPQ$ l\u00e0 h\u00ecnh thoi. <br\/> \u0110\u1ec3 t\u1ed3n t\u1ea1i \u0111i\u1ec3m $H$ th\u1ecfa m\u00e3n th\u00ec $BC$ kh\u00f4ng l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t trong tam gi\u00e1c $ABC$. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang. <\/span><\/span> ","column":2}]}],"id_ques":1549},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang ho\u1eb7c sai","title_trans":"\u0110\u1ec1 chung cho b\u1ed1n c\u00e2u","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":" <span class='basic_left'> Cho $\\Delta ABC$ v\u00e0 \u0111i\u1ec3m $H$ thu\u1ed9c mi\u1ec1n trong c\u1ee7a tam gi\u00e1c. G\u1ecdi $M, N, P, Q$ theo th\u1ee9 t\u1ef1 l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u00e1c \u0111o\u1ea1n th\u1eb3ng $HB, HC, AC, AB$. <br\/><br\/> <b> C\u00e2u 4:<\/b> \u0110i\u1ec3m $H$ n\u1eb1m tr\u00ean \u0111\u01b0\u1eddng cao xu\u1ea5t ph\u00e1t t\u1eeb \u0111\u1ec9nh $A$ c\u1ee7a $\\Delta ABC$ th\u00ec $MNPQ$ l\u00e0 h\u00ecnh vu\u00f4ng. <\/span>","select":[" \u0110\u00fang "," Sai"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai9/lv3/img\/H819_K1_5.jpg' \/><\/center> Theo c\u00e2u 1, ta ch\u1ee9ng minh \u0111\u01b0\u1ee3c $MNPQ$ l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh <br\/> Theo c\u00e2u 3, \u0111\u1ec3 $MNPQ$ l\u00e0 h\u00ecnh thoi th\u00ec $MN=MQ$ <br\/> \u0110\u1ec3 $MNPQ$ l\u00e0 h\u00ecnh vu\u00f4ng th\u00ec $MN\\bot MQ$ v\u00e0 $MN=MQ$ <br\/> V\u1eady \u0111i\u1ec3m $H$ v\u1eeba n\u1eb1m tr\u00ean \u0111\u01b0\u1eddng cao h\u1ea1 t\u1eeb \u0111\u1ec9nh $A$ c\u1ee7a $\\Delta ABC$ v\u1eeba ch\u1ea1y tr\u00ean cung tr\u00f2n thu\u1ed9c \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $A$, b\u00e1n k\u00ednh $BC$ (ph\u1ea7n cung tr\u00f2n thu\u1ed9c mi\u1ec1n trong $\\Delta ABC$) <br\/> \u0110\u1ec3 t\u1ed3n t\u1ea1i \u0111i\u1ec3m $H$ th\u1ecfa m\u00e3n th\u00ec $BC$ kh\u00f4ng l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t trong tam gi\u00e1c $ABC$. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 Sai. <\/span><\/span> ","column":2}]}],"id_ques":1550}],"lesson":{"save":0,"level":3}}