{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" <span class='basic_left'> Tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a h\u00ecnh thang c\u00e2n l\u00e0: <\/span>","select":["A. \u0110\u01b0\u1eddng th\u1eb3ng \u0111i qua trung \u0111i\u1ec3m hai c\u1ea1nh b\u00ean c\u1ee7a h\u00ecnh thang c\u00e2n","B. \u0110\u01b0\u1eddng ch\u00e9o h\u00ecnh thang c\u00e2n","C. \u0110\u01b0\u1eddng th\u1eb3ng vu\u00f4ng g\u00f3c v\u1edbi hai \u0111\u00e1y c\u1ee7a h\u00ecnh thang c\u00e2n","D. \u0110\u01b0\u1eddng th\u1eb3ng \u0111i qua trung \u0111i\u1ec3m hai \u0111\u00e1y h\u00ecnh thang c\u00e2n"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_1.jpg' \/><\/center> C\u00e2u D l\u00e0 \u0111\u00fang <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D. <\/span><\/span> ","column":1}]}],"id_ques":1401},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" <span class='basic_left'> Ch\u1ecdn kh\u1eb3ng \u0111\u1ecbnh <b>sai<\/b> trong c\u00e1c kh\u1eb3ng \u0111\u1ecbnh sau: <\/span>","select":["A. N\u1ebfu hai g\u00f3c \u0111\u1ed1i x\u1ee9ng v\u1edbi nhau qua m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng th\u00ec ch\u00fang b\u1eb1ng nhau","B. N\u1ebfu hai tam gi\u00e1c \u0111\u1ed1i x\u1ee9ng v\u1edbi nhau qua m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng th\u00ec ch\u00fang b\u1eb1ng nhau","C. N\u1ebfu hai tam gi\u00e1c \u0111\u1ed1i x\u1ee9ng v\u1edbi nhau qua m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng th\u00ec chu vi c\u1ee7a ch\u00fang b\u1eb1ng nhau","D. N\u1ebfu hai tia \u0111\u1ed1i x\u1ee9ng nhau qua m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng th\u00ec ch\u00fang b\u1eb1ng nhau"],"explain":" <span class='basic_left'> C\u00e2u D l\u00e0 kh\u1eb3ng \u0111\u1ecbnh sai v\u00ec kh\u00f4ng c\u00f3 kh\u00e1i ni\u1ec7m hai tia b\u1eb1ng nhau. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D. <\/span><\/span> ","column":1}]}],"id_ques":1402},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> Cho $\\Delta ABC$ \u0111\u1ec1u, c\u00e1c \u0111\u01b0\u1eddng cao $AA', BB', CC'$. Tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a tam gi\u00e1c $ABC$ l\u00e0: <\/span>","select":["A. C\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng $AA'; BB'; CC'$","B. \u0110\u01b0\u1eddng th\u1eb3ng $ CC'$","C. \u0110\u01b0\u1eddng th\u1eb3ng $AA'$","D. \u0110\u01b0\u1eddng th\u1eb3ng $ BB'$"],"explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_2.jpg' \/> <span class='basic_left'> Do $\\Delta ABC$ \u0111\u1ec1u n\u00ean tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a n\u00f3 l\u00e0 c\u00e1c \u0111\u01b0\u1eddng cao h\u1ea1 t\u1eeb c\u00e1c \u0111\u1ec9nh \u0111\u1ebfn c\u00e1c c\u1ea1nh t\u01b0\u01a1ng \u1ee9ng. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 $A$. <\/span> <br\/><br\/> <b> L\u01b0u \u00fd: <\/b> <i> \u0110\u01b0\u1eddng th\u1eb3ng $d$ g\u1ecdi l\u00e0 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a h\u00ecnh $\\mathbb{H}$ n\u1ebfu \u0111i\u1ec3m \u0111\u1ed1i x\u1ee9ng v\u1edbi m\u1ed7i \u0111i\u1ec3m thu\u1ed9c h\u00ecnh $\\mathbb{H}$ qua \u0111\u01b0\u1eddng th\u1eb3ng $d$ c\u0169ng thu\u1ed9c h\u00ecnh $\\mathbb{H}$ <\/i><\/span> ","column":2}]}],"id_ques":1403},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t <br\/> Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0111\u00fang hay sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> Hai \u0111i\u1ec3m $A$ v\u00e0 $A'$ \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u0111\u1ed1i x\u1ee9ng nhau qua \u0111\u01b0\u1eddng th\u1eb3ng $d$ n\u1ebfu $d$ l\u00e0 trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n th\u1eb3ng $AA'$. <\/span>","select":["\u0110\u00fang","Sai"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_3.jpg' \/><\/center><br\/> V\u00ec $d$ l\u00e0 \u0111\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n th\u1eb3ng $AA'$ n\u00ean $d$ vu\u00f4ng g\u00f3c v\u1edbi $AA'$ v\u00e0 $d$ \u0111i qua trung \u0111i\u1ec3m c\u1ee7a \u0111o\u1ea1n th\u1eb3ng $AA'$ <span class='basic_left'> Kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 <b>\u0111\u00fang<\/b> <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang <\/span> <\/span> ","column":2}]}],"id_ques":1404},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t <br\/> Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0111\u00fang hay sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> T\u00e2m \u0111\u1ed1i x\u1ee9ng c\u1ee7a m\u1ed9t \u0111o\u1ea1n th\u1eb3ng l\u00e0 trung \u0111i\u1ec3m c\u1ee7a \u0111o\u1ea1n th\u1eb3ng \u0111\u00f3. <\/span>","select":["\u0110\u00fang","Sai"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_4.jpg' \/><\/center> T\u00e2m \u0111\u1ed1i x\u1ee9ng c\u1ee7a \u0111o\u1ea1n th\u1eb3ng $AA'$ l\u00e0 trung \u0111i\u1ec3m $P$ c\u1ee7a n\u00f3. <br\/> Kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 <b>\u0111\u00fang<\/b> <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang <\/span> <\/span> ","column":2}]}],"id_ques":1405},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t <br\/> Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0111\u00fang hay sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> H\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 t\u00e2m \u0111\u1ed1i x\u1ee9ng l\u00e0 giao \u0111i\u1ec3m c\u1ee7a hai \u0111\u01b0\u1eddng ch\u00e9o. <\/span>","select":["\u0110\u00fang","Sai"],"explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_5.jpg' \/><\/center> H\u00ecnh b\u00ecnh h\u00e0nh c\u00f3 t\u00e2m \u0111\u1ed1i x\u1ee9ng l\u00e0 giao \u0111i\u1ec3m c\u1ee7a hai \u0111\u01b0\u1eddng ch\u00e9o. <br\/> Kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 <b>\u0111\u00fang<\/b> <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang <\/span> <\/span> ","column":2}]}],"id_ques":1406},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["2"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> H\u00ecnh ch\u1eef nh\u1eadt c\u00f3 bao nhi\u00eau tr\u1ee5c \u0111\u1ed1i x\u1ee9ng? <br\/><br\/> <b> \u0110\u00e1p \u00e1n:<\/b> c\u00f3 $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ tr\u1ee5c \u0111\u1ed1i x\u1ee9ng <\/span> ","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_6.jpg' \/><\/center> <span class='basic_left'> H\u00ecnh ch\u1eef nh\u1eadt c\u00f3 hai tr\u1ee5c \u0111\u1ed1i x\u1ee9ng $d_1$ v\u00e0 $d_2$ nh\u01b0 tr\u00ean h\u00ecnh v\u1ebd. <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o c\u00e1c \u00f4 tr\u1ed1ng l\u00e0 $2$. <\/span><\/span> "}]}],"id_ques":1407},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["3"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> Tam gi\u00e1c \u0111\u1ec1u c\u00f3 bao nhi\u00eau tr\u1ee5c \u0111\u1ed1i x\u1ee9ng? <br\/><br\/> <b> \u0110\u00e1p \u00e1n:<\/b> c\u00f3 $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ tr\u1ee5c \u0111\u1ed1i x\u1ee9ng <\/span> ","explain":" V\u1ebd h\u00ecnh <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_7.jpg' \/><\/center> <span class='basic_left'> Tam gi\u00e1c \u0111\u1ec1u c\u00f3 3 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng l\u00e0 c\u00e1c \u0111\u01b0\u1eddng cao c\u1ee7a tam gi\u00e1c \u0111\u00f3. <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o c\u00e1c \u00f4 tr\u1ed1ng l\u00e0 $3$. <\/span><\/span> "}]}],"id_ques":1408},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["1"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> H\u00ecnh thang c\u00e2n c\u00f3 bao nhi\u00eau tr\u1ee5c \u0111\u1ed1i x\u1ee9ng? <br\/><br\/> <b> \u0110\u00e1p \u00e1n:<\/b> c\u00f3 $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ tr\u1ee5c \u0111\u1ed1i x\u1ee9ng <\/span> ","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_8.jpg' \/><\/center> <span class='basic_left'> H\u00ecnh thang c\u00e2n c\u00f3 1 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng nh\u01b0 h\u00ecnh v\u1ebd tr\u00ean. <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o c\u00e1c \u00f4 tr\u1ed1ng l\u00e0 $1$. <\/span><\/span> "}]}],"id_ques":1409},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["3"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> C\u00e1c \u0111i\u1ec3m $A', B', C'$ th\u1eb3ng h\u00e0ng v\u00e0 \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A, B, C$ qua \u0111\u01b0\u1eddng th\u1eb3ng $d$. Bi\u1ebft $A$ n\u1eb1m gi\u1eefa $B$ v\u00e0 $C$; $AC=4\\, cm; CB=7\\, cm$. T\u00ednh \u0111\u1ed9 d\u00e0i $A'B'$. <br\/><br\/> <b> \u0110\u00e1p \u00e1n:<\/b> $A'B'=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ $(cm)$ <\/span> ","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_9.jpg' \/><\/center> C\u00e1c \u0111i\u1ec3m $A', B', C'$ \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A, B, C$ qua \u0111\u01b0\u1eddng th\u1eb3ng $d$.<br\/> M\u00e0 $AC=4\\, cm \\Rightarrow A'C'=4\\, cm$ <br\/> $BC=7\\, cm \\Rightarrow B'C'=7\\, cm$ <br\/> Do $A', B', C'$ th\u1eb3ng h\u00e0ng m\u00e0 $A$ n\u1eb1m gi\u1eefa $B$ v\u00e0 $C$ n\u00ean $A'$ n\u1eb1m gi\u1eefa $B'$ v\u00e0 $C'$, hay: $B'A'+A'C'=B'C'$ <br\/> $\\Rightarrow B'A'=B'C'-A'C'=7-4=3$ $(cm)$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $3$. <\/span> <br\/> <b> L\u01b0u \u00fd: <\/b> <i> Hai \u0111i\u1ec3m $A, B$ \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A', B'$ qua \u0111\u01b0\u1eddng th\u1eb3ng $d$ th\u00ec $AB=A'B'$. <\/i> <\/span> "}]}],"id_ques":1410},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["16"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> Cho $\\Delta ABC$ c\u00e2n t\u1ea1i $A$ c\u00f3 $AB=6\\, cm; BC=4\\, cm$. V\u1ebd $\\Delta A'BC$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $\\Delta ABC$ qua c\u1ea1nh $BC$. Chu vi $\\Delta A'BC$ l\u00e0 $=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}$ $(cm)$ <\/span> ","hint":" D\u1ef1a v\u00e0o t\u00ednh ch\u1ea5t \u0111\u1ed1i x\u1ee9ng tr\u1ee5c \u0111\u1ec3 t\u00ednh.","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_10.jpg' \/><\/center> Do $\\Delta A'BC$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $\\Delta ABC$ qua c\u1ea1nh $BC$ n\u00ean $A'B=AB$. <br\/> $\\Rightarrow A'B= AB=6\\, (cm)$ <br\/> M\u00e0 $\\Delta ABC$ c\u00e2n t\u1ea1i $A$ n\u00ean $\\Delta A'BC$ c\u00e2n t\u1ea1i $A'$. <br\/> $\\Rightarrow A'B=A'C=6\\, (cm)$ <br\/> Chu vi $\\Delta A'BC$ l\u00e0: $A'B+A'C+ BC=6+6+4=16\\, (cm)$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o c\u00e1c \u00f4 tr\u1ed1ng l\u00e0 $16$. <\/span> <br\/> <b> L\u01b0u \u00fd: <\/b> <i> Hai \u0111i\u1ec3m $A, B$ \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A', B'$ qua \u0111\u01b0\u1eddng th\u1eb3ng $d$ th\u00ec $AB=A'B'$. <\/i> <\/span> "}]}],"id_ques":1411},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> H\u00ecnh n\u00e0o v\u1ebd \u0111\u00fang tr\u1ee5c \u0111\u1ed1i x\u1ee9ng $d$ c\u1ee7a h\u00ecnh thang c\u00e2n <br\/> <img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_11.jpg' \/> <img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_11b.jpg' \/> <img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_11d.jpg' \/> <\/span>","select":["A. H\u00ecnh 1","B. H\u00ecnh 2","C. H\u00ecnh 3 "],"explain":" <span class='basic_left'> H\u00ecnh 1 v\u1ebd \u0111\u00fang tr\u1ee5c \u0111\u1ed1i x\u1ee9ng $d$ c\u1ee7a h\u00ecnh thang c\u00e2n. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A. <\/span><\/span> ","column":3}]}],"id_ques":1412},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":" <span class='basic_left'> H\u00ecnh n\u00e0o v\u1ebd \u0111\u00fang tr\u1ee5c \u0111\u1ed1i x\u1ee9ng $m$ c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt <br\/> <img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_12b.jpg' \/> <img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_12a.jpg' \/> <img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_12c.jpg' \/> <\/span>","select":["A. H\u00ecnh 1","B. H\u00ecnh 2","C. H\u00ecnh 3 ","D. H\u00ecnh 1 v\u00e0 h\u00ecnh 2"],"explain":" <span class='basic_left'> H\u00ecnh 1 v\u00e0 h\u00ecnh 2 v\u1ebd \u0111\u00fang tr\u1ee5c \u0111\u1ed1i x\u1ee9ng $m$ c\u1ee7a h\u00ecnh ch\u1eef nh\u1eadt. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D. <\/span><\/span> ","column":2}]}],"id_ques":1413},{"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":[[["="]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> Cho $\\widehat{xOy}=50^o$, \u0111i\u1ec3m $A$ n\u1eb1m trong g\u00f3c \u0111\u00f3. V\u1ebd \u0111i\u1ec3m $B$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $A$ qua $Ox$, v\u1ebd \u0111i\u1ec3m $C$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $A$ qua $Oy$. <br\/><br\/> <b> C\u00e2u 1:<\/b> So s\u00e1nh $OB$ v\u00e0 $OC$. <br\/><br\/> <b> \u0110\u00e1p \u00e1n: <\/b> $OB\\, \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\, OC$ (\u0110i\u1ec1n d\u1ea5u > ; < ho\u1eb7c =) <\/span> ","hint":"G\u1ecdi $AB\\cap Ox=H$ v\u00e0 $AC\\cap Oy=K$ <br\/> So s\u00e1nh $OC$, $OB$ v\u1edbi $OA$. ","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_13.jpg' \/><\/center> <span class='basic_left'> G\u1ecdi $AB\\cap Ox=H$ v\u00e0 $AC\\cap Oy=K$<br\/> Theo b\u00e0i, $B$ l\u00e0 \u0111i\u1ec3m \u0111\u1ed1i x\u1ee9ng v\u1edbi $A$ qua $Ox$ n\u00ean $AH = BH$. <br\/> $\\Rightarrow OH$ l\u00e0 trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n $AB$ <br\/> Do \u0111\u00f3 $OB=OA$ (1) <br\/> T\u01b0\u01a1ng t\u1ef1, $C$ l\u00e0 \u0111i\u1ec3m \u0111\u1ed1i x\u1ee9ng v\u1edbi $A$ qua $Oy$ n\u00ean $AK=CK$. <br\/> $\\Rightarrow OK$ l\u00e0 trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n $AC$ <br\/> $\\Rightarrow OC=OA$ (2) <br\/> T\u1eeb (1) v\u00e0 (2) suy ra $OB=OC$. <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng d\u1ea5u '='. <\/span><\/span> "}]}],"id_ques":1414},{"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":[[["100"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> Cho $\\widehat{xOy}=50^o$, \u0111i\u1ec3m $A$ n\u1eb1m trong g\u00f3c \u0111\u00f3. V\u1ebd \u0111i\u1ec3m $B$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $A$ qua $Ox$, v\u1ebd \u0111i\u1ec3m $C$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $A$ qua $Oy$. <br\/><br\/> <b> C\u00e2u 2:<\/b> T\u00ednh $\\widehat{BOC}$. <br\/><br\/> <b> \u0110\u00e1p \u00e1n: <\/b> $\\widehat{BOC}= \\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}^o$ <\/span> ","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_13.jpg' \/><\/center> <span class='basic_left'> Theo b\u00e0i, $OB$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $OA$ qua $Ox$ n\u00ean $\\widehat {BOx}$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $\\widehat {AOx}$ qua $Ox$. <br\/> $\\Rightarrow \\widehat {AOx}=\\widehat {BOx}$ (*) <br\/> T\u01b0\u01a1ng t\u1ef1: $\\widehat{COy}$ \u0111\u1ed1i x\u1ee9ng v\u1edbi $\\widehat{AOy}$ qua $Oy$. <br\/> $\\Rightarrow \\widehat {AOy}=\\widehat {COy}$ (**) <br\/> T\u1eeb (*) v\u00e0 (**) $\\Rightarrow \\widehat{BOC}=\\widehat{BOx}+\\widehat{xOy}+\\widehat{COy}$$=2\\widehat{xOy}$ (***) <br\/> M\u00e0 $\\widehat{xOy}=50^o$ <br\/> T\u1eeb (***) $\\Rightarrow \\widehat{BOC}=2.50^o=100^o$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $100$. <\/span><\/span> "}]}],"id_ques":1415},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t <br\/> Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0111\u00fang hay sai","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> Cho h\u00ecnh thang c\u00e2n $ABCD\\, (AB \/\/ CD; AB > CD)$ . Hai tia $AD$ v\u00e0 $BC$ c\u1eaft nhau t\u1ea1i \u0111i\u1ec3m $E$. Hai \u0111i\u1ec3m $M$ v\u00e0 $N$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u00e1c c\u1ea1nh \u0111\u00e1y $AB, CD$. <br\/><br\/> <b> C\u00e2u 1:<\/b> Ta ch\u1ee9ng minh \u0111\u01b0\u1ee3c $E, N, M$ th\u1eb3ng h\u00e0ng. <\/span>","select":["\u0110\u00fang","Sai"],"explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_14.jpg' \/><\/center> <span class='basic_left'> Ta c\u00f3: $ABCD$ l\u00e0 h\u00ecnh thang c\u00e2n (gi\u1ea3 thi\u1ebft)<br\/>$\\Rightarrow$ $\\widehat {A}=\\widehat{B}$ (t\u00ednh ch\u1ea5t) <br\/> $\\Rightarrow \\Delta ABE$ c\u00e2n t\u1ea1i $E$ (t\u00ednh ch\u1ea5t). <br\/> $\\Rightarrow EM\\bot AB$ (1)<br\/> M\u1eb7t kh\u00e1c $M, N$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $AB$ v\u00e0 $CD$ (gi\u1ea3 thi\u1ebft)<br\/>$\\Rightarrow$ $MN$ l\u00e0 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a h\u00ecnh thang $ABCD$.<br\/> $\\Rightarrow$ $MN\\bot AB$ (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow E, M, N$ th\u1eb3ng h\u00e0ng. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang. <\/span> <\/span> ","column":2}]}],"id_ques":1416},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t <br\/> Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0111\u00fang hay sai","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" <span class='basic_left'> Cho h\u00ecnh thang c\u00e2n $ABCD\\, (AB \/\/ CD; AB > CD)$ . Hai tia $AD$ v\u00e0 $BC$ c\u1eaft nhau t\u1ea1i \u0111i\u1ec3m $E$. Hai \u0111i\u1ec3m $M$ v\u00e0 $N$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u00e1c c\u1ea1nh \u0111\u00e1y $AB, CD$. <br\/><br\/> <b> C\u00e2u 2:<\/b> $ABCD$ c\u00f3 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng l\u00e0 $BD$ v\u00e0 $AC$. <\/span>","select":["\u0110\u00fang","Sai"],"explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop8/toan/hinhhoc/bai5/lv1/img\/H815_D1_14b.jpg' \/><\/center> <span class='basic_left'> Tr\u1ee5c \u0111\u1ed1i x\u1ee9ng c\u1ee7a h\u00ecnh thang c\u00e2n $ABCD$ l\u00e0 $EM$. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 Sai. <\/span> <\/span> ","column":2}]}],"id_ques":1417},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["36"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> C\u00e1c \u0111i\u1ec3m $A', B', C'$ l\u1ea7n l\u01b0\u1ee3t \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A, B, C$ qua t\u00e2m \u0111\u1ed1i x\u1ee9ng $O$. <br\/> Bi\u1ebft chu vi $\\Delta ABC$ l\u00e0 $36\\, cm$ th\u00ec chu vi $\\Delta A'B'C'$ l\u00e0 $\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\, (cm)$ <\/span> ","explain":" <span class='basic_left'> Do c\u00e1c \u0111i\u1ec3m $A', B', C'$ l\u1ea7n l\u01b0\u1ee3t \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A, B, C$ qua t\u00e2m \u0111\u1ed1i x\u1ee9ng $O$. <br\/> $\\Rightarrow AB=A'B'$ ;$CA=C'A'$; $BC=B'C'$ <br\/> Do \u0111\u00f3 hai tam gi\u00e1c $ABC$ v\u00e0 $A'B'C'$ c\u00f3 chu vi b\u1eb1ng nhau. <br\/> T\u1ee9c l\u00e0 chu vi $\\Delta A'B'C'$ l\u00e0 $36\\, (cm)$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $36$. <\/span> <\/span> "}]}],"id_ques":1418},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["5"]]],"list":[{"point":5,"width":20,"type_input":"","ques":"<span class='basic_left'> C\u00e1c \u0111i\u1ec3m $A', B', C'$ l\u1ea7n l\u01b0\u1ee3t \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A, B, C$ qua t\u00e2m \u0111\u1ed1i x\u1ee9ng $O$. C\u00e1c \u0111i\u1ec3m $A', B', C'$ th\u1eb3ng h\u00e0ng ($C'$ n\u1eb1m gi\u1eefa $A'$ v\u00e0 $B'$) n\u1ebfu $AB=12\\, cm$; $C'A'=7 cm$ th\u00ec $BC=\\FormInput[40][bl_elm_true basic_elm basic_blank basic_blank_part]{}\\, (cm)$ <\/span> ","explain":" <span class='basic_left'> Do c\u00e1c \u0111i\u1ec3m $A', B', C'$ l\u1ea7n l\u01b0\u1ee3t \u0111\u1ed1i x\u1ee9ng v\u1edbi c\u00e1c \u0111i\u1ec3m $A, B, C$ qua t\u00e2m \u0111\u1ed1i x\u1ee9ng $O$. <br\/> $\\Rightarrow AB=A'B'=12\\, cm$ ;$CA=C'A'=7\\, cm$; $BC=B'C'$ <br\/> \u0110\u1ec3 ba \u0111i\u1ec3m $A', B', C'$ th\u1eb3ng h\u00e0ng ( $C'$ n\u1eb1m gi\u1eefa $A'$ v\u00e0 $B'$) th\u00ec: <br\/> $A'C'+C'B'=A'B'$ <br\/> T\u1ee9c l\u00e0: $7+C'B'=12$ <br\/> $\\Rightarrow C'B'=12-7=5\\, (cm)$ <br\/> Do \u0111\u00f3: $BC=5\\, (cm)$ <br\/> <span class='basic_pink'> V\u1eady c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0 $5$. <\/span> <br\/> <b> L\u01b0u \u00fd: <\/b> <i> \u0110\u1ec3 ba \u0111i\u1ec3m $A, B, C$ th\u1eb3ng h\u00e0ng ($B$ n\u1eb1m gi\u1eefa $A$ v\u00e0 $C$) th\u00ec: $AB+BC=AC$. <\/i> <\/span> "}]}],"id_ques":1419},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t <br\/> Kh\u1eb3ng \u0111\u1ecbnh sau \u0111\u00e2y \u0111\u00fang hay sai","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" <span class='basic_left'> H\u00ecnh thang vu\u00f4ng kh\u00f4ng c\u00f3 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng. <\/span>","select":["\u0110\u00fang","Sai"],"explain":" <span class='basic_left'> H\u00ecnh thang vu\u00f4ng kh\u00f4ng c\u00f3 tr\u1ee5c \u0111\u1ed1i x\u1ee9ng. <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 \u0110\u00fang. <\/span> <\/span> ","column":2}]}],"id_ques":1420}],"lesson":{"save":0,"level":1}}