{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"T\u1eeb m\u1ed9t \u0111i\u1ec3m $A$ kh\u00f4ng n\u1eb1m tr\u00ean \u0111\u01b0\u1eddng th\u1eb3ng $d$, k\u1ebb \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c $AH$ v\u00e0 m\u1ed9t \u0111\u01b0\u1eddng xi\u00ean $AB$ t\u00f9y \u00fd \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $d$. Kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. $AH > AB$ ","B. $AH = AB$","C. $AH < AB$"],"hint":"D\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D01.png' \/><\/center> <br\/> Ta c\u00f3 $AH$ l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c, $AB$ l\u00e0 \u0111\u01b0\u1eddng xi\u00ean <br\/> N\u00ean $AH < AB$ (quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: C <\/span> <br\/> <span class='basic_green'> <i>Nh\u1eadn x\u00e9t: Ngo\u00e0i c\u00e1ch tr\u00ean ta c\u00f3 th\u1ec3 l\u00e0m theo c\u00e1ch sau: <br\/> X\u00e9t $\\triangle{ABH}$ c\u00f3 $\\widehat{H} = 90^{o}$ (gt) <br\/> $\\Rightarrow$ $AB$ l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t (trong tam gi\u00e1c vu\u00f4ng c\u1ea1nh huy\u1ec1n l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t) <br\/> $\\Rightarrow$ $AB > AH$ <\/span> ","column":3}]}],"id_ques":1831},{"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":"Cho h\u00ecnh v\u1ebd: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D02.png' \/><\/center><br\/> Kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. $AH < AN < AP$ ","B. $AH < AP < AM$","C. $AN < AP < AM$","D. $AM > AN > AP$"],"hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D02.png' \/><\/center> <br\/> Quan s\u00e1t h\u00ecnh v\u1ebd ta th\u1ea5y: $HM < HN < HP$ <br\/> N\u00ean $ AM < AN < AP$ (\u0111\u01b0\u1eddng xi\u00ean n\u00e0o c\u00f3 h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n th\u00ec l\u1edbn h\u01a1n) <br\/> M\u00e0 $AH$ l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c n\u00ean: $AH < AM < AN < AP$ (\u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c l\u00e0 \u0111\u01b0\u1eddng ng\u1eafn nh\u1ea5t) <br\/> $\\Rightarrow$ $AH < AM < AN < AP$ <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span> ","column":2}]}],"id_ques":1832},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Cho h\u00ecnh v\u1ebd: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D03.png' \/><\/center><br\/> Kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. $AB = AC$ ","B. $AB > AC$","C. $AB < AC$"],"hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D03.png' \/><\/center> <br\/>$\\triangle{ABC}$ c\u00f3: $BH = 2cm$; $HC = 4cm$ <br\/> $\\Rightarrow BH < HC$ $\\Rightarrow$ $AB < AC$ (\u0111\u01b0\u1eddng xi\u00ean n\u00e0o c\u00f3 h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n th\u00ec l\u1edbn h\u01a1n) <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: C <\/span> ","column":3}]}],"id_ques":1833},{"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":"Cho h\u00ecnh v\u1ebd: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D04.png' \/><\/center> <br\/> Tam gi\u00e1c $ABC$ c\u00e2n t\u1ea1i $A$. <b> \u0110\u00fang <\/b> hay <b> sai <\/b>? ","select":["A. \u0110\u00daNG ","B. SAI"],"hint":"","explain":" <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D04.png' \/><\/center> <br\/>$\\triangle{ABC}$ c\u00f3: $HB = HC$ <br\/> $\\Rightarrow AB = AC$ (hai h\u00ecnh chi\u1ebfu b\u1eb1ng nhau th\u00ec hai \u0111\u01b0\u1eddng xi\u00ean b\u1eb1ng nhau) <br\/> $\\Rightarrow$ $\\triangle{ABC}$ c\u00e2n t\u1ea1i $A$ (\u0111\u1ecbnh ngh\u0129a tam gi\u00e1c c\u00e2n) <br\/> V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 <span class='basic_pink'> \u0110\u00daNG <\/span> ","column":3}]}],"id_ques":1834},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Cho h\u00ecnh v\u1ebd: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D05.png' \/><\/center> <br\/> Khi \u0111\u00f3 $MN > MP$. <b> \u0110\u00fang <\/b> hay <b> sai <\/b>? ","select":["A. \u0110\u00daNG ","B. SAI"],"hint":"","explain":" Ta c\u00f3, $IN < IP$ $\\Rightarrow$ $MN < MP$ (h\u00ecnh chi\u1ebfu nh\u1ecf h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean nh\u1ecf h\u01a1n) <br\/> V\u1eady kh\u1eb3ng \u0111\u1ecbnh $MN > MP$ l\u00e0 <span class='basic_pink'> SAI <\/span> <br\/> <span class='basic_left'><span class='basic_green'> <i> Nh\u1eadn x\u00e9t: <br\/> Ngo\u00e0i c\u00e1ch tr\u00ean ta c\u00f3 th\u1ec3 l\u00e0m nh\u01b0 sau: <br\/> $\\triangle{MIN}$ c\u00f3 $\\widehat{MNP}$ l\u00e0 g\u00f3c ngo\u00e0i t\u1ea1i \u0111\u1ec9nh $N$ <br\/> $\\Rightarrow$ $\\widehat{MNP} > \\widehat{I} = 90^{o}$ <br\/> $\\triangle{MNP}$ c\u00f3 $\\widehat{MNP} > 90^{o}$ n\u00ean $MP > MN$ (c\u1ea1nh \u0111\u1ed1i di\u1ec7n v\u1edbi g\u00f3c t\u00f9 l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t trong tam gi\u00e1c) <\/i> <\/span> ","column":3}]}],"id_ques":1835},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Cho h\u00ecnh v\u1ebd: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D05.png' \/><\/center> <br\/> Kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. $MP < KN$ ","B. $MP > KN$","C. $MP = KN$"],"hint":"","explain":" $IN < IP \\Rightarrow MN < MP$ (h\u00ecnh chi\u1ebfu nh\u1ecf h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean nh\u1ecf h\u01a1n) (1) <br\/> $IK < IM \\Rightarrow KN < MN$ (h\u00ecnh chi\u1ebfu nh\u1ecf h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean nh\u1ecf h\u01a1n) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $KN < MP$ <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B <\/span> <br\/> <span class='basic_left'><span class='basic_green'> <i> Nh\u1eadn x\u00e9t: <br\/> Ngo\u00e0i c\u00e1ch tr\u00ean ta c\u00f3 th\u1ec3 l\u00e0m nh\u01b0 sau: <br\/> $\\triangle{IKN}$ c\u00f3 $\\widehat{MKN}$ l\u00e0 g\u00f3c ngo\u00e0i t\u1ea1i \u0111\u1ec9nh $K$ <br\/> $\\Rightarrow$ $\\widehat{MKN} > \\widehat{I} = 90^{o}$ <br\/> $\\triangle{MKN}$ c\u00f3 $\\widehat{MKN} > 90^{o}$ n\u00ean $MN > KN$ (c\u1ea1nh \u0111\u1ed1i di\u1ec7n v\u1edbi g\u00f3c t\u00f9 l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t trong tam gi\u00e1c) (1) <br\/> $\\triangle{MIN}$ c\u00f3 $\\widehat{MNP}$ l\u00e0 g\u00f3c ngo\u00e0i t\u1ea1i \u0111\u1ec9nh $N$ <br\/> $\\Rightarrow$ $\\widehat{MNP} > \\widehat{I} = 90^{o}$ <br\/> $\\triangle{MNP}$ c\u00f3 $\\widehat{MNP} > 90^{o}$ n\u00ean $MP > MN$ (c\u1ea1nh \u0111\u1ed1i di\u1ec7n v\u1edbi g\u00f3c t\u00f9 l\u00e0 c\u1ea1nh l\u1edbn nh\u1ea5t trong tam gi\u00e1c) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $MP > KN$ <\/i> <\/span> ","column":3}]}],"id_ques":1836},{"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":"Cho $\\triangle{ABC}$ c\u00e2n t\u1ea1i $A$, k\u1ebb $AH \\perp BC$ $(H \\in BC)$. Tr\u00ean c\u00e1c \u0111o\u1ea1n th\u1eb3ng $HB$ v\u00e0 $HC$, l\u1ea5y c\u00e1c \u0111i\u1ec3m $D$ v\u00e0 $E$ sao cho $BD = CE$. H\u00e3y so s\u00e1nh \u0111\u1ed9 d\u00e0i $AD$ v\u00e0 $AE$ b\u1eb1ng c\u00e1ch x\u00e9t hai h\u00ecnh chi\u1ebfu. ","select":["A. $AD = AE$ ","B. $AD > AE$","C. $AD < AE$"],"hint":"So s\u00e1nh \u0111\u1ed9 d\u00e0i $HD$ v\u00e0 $HE$","explain":" <span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D06.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> $AB = AC \\Rightarrow HB = HC$ (hai \u0111\u01b0\u1eddng xi\u00ean b\u1eb1ng nhau th\u00ec hai h\u00ecnh chi\u1ebfu b\u1eb1ng nhau) (1) <br\/> $BD = EC$ (gt) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $HB - BD = HC - EC$ hay $HD = HE$ <br\/> $\\Rightarrow$ $AD = AE$ (hai h\u00ecnh chi\u1ebfu b\u1eb1ng nhau th\u00ec hai \u0111\u01b0\u1eddng xi\u00ean b\u1eb1ng nhau) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span> ","column":3}]}],"id_ques":1837},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D07.png' \/><\/center> <br\/> Cho $\\triangle{MNP}$ c\u00e2n t\u1ea1i $M$, tr\u00ean tia \u0111\u1ed1i c\u1ee7a tia $PN$ l\u1ea5y \u0111i\u1ec3m $K$. So s\u00e1nh \u0111\u1ed9 d\u00e0i $MK$ v\u00e0 $MN$ b\u1eb1ng c\u00e1ch x\u00e9t hai h\u00ecnh chi\u1ebfu. ","select":["A. $MK < MN$ ","B. $MK > MN$","C. $MK = MN$"],"hint":"So s\u00e1nh \u0111\u1ed9 d\u00e0i $ON$ v\u00e0 $OK$","explain":" <span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D07.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> $\\triangle{MNP}$ c\u00e2n t\u1ea1i $M$ (gt), suy ra $MN = MP$ (t\u00ednh ch\u1ea5t) <br\/> V\u00ec $MN = MP \\Rightarrow ON = OP$ (quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu) (1) <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $OK > OP$ (do $O$ v\u00e0 $K$ n\u1eb1m kh\u00e1c ph\u00eda \u0111\u1ed1i v\u1edbi \u0111i\u1ec3m $P$) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $OK > ON$ <br\/> V\u00ec $OK > ON$ n\u00ean $MK > MN$ (quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B <\/span> ","column":3}]}],"id_ques":1838},{"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":"Cho $\\triangle{ABC}$ c\u00f3 $\\widehat{B} > \\widehat{C}$. K\u1ebb $AH \\perp BC$ $(H \\in BC)$. H\u00e3y so s\u00e1nh \u0111\u1ed9 d\u00e0i $HB$ v\u00e0 $HC$. ","select":["A. $HB < HC$ ","B. $HB > HC$","C. $HB = HC$"],"hint":"So s\u00e1nh \u0111\u1ed9 d\u00e0i hai \u0111\u01b0\u1eddng xi\u00ean $AB$ v\u00e0 $AC$","explain":" <span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D08.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> $\\triangle{ABC}$ c\u00f3 $\\widehat{B} > \\widehat{C}$ <br\/> $\\Rightarrow$ $AC > AB$ (quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong $\\triangle{ABC}$) <br\/> V\u00ec $AC > AB$ n\u00ean $HC > HB$ (quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span> ","column":3}]}],"id_ques":1839},{"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":"Cho h\u00ecnh v\u1ebd: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D09.png' \/><\/center> <br\/> Bi\u1ebft $IP > IM$, h\u00e3y so s\u00e1nh $\\widehat{NMP}$ v\u00e0 $\\widehat{NPM}$ ","select":["A. $\\widehat{NMP} > \\widehat{NPM}$ ","B. $\\widehat{NMP} < \\widehat{NPM}$","C. $\\widehat{NMP} = \\widehat{NPM} $"],"hint":"So s\u00e1nh \u0111\u1ed9 d\u00e0i hai \u0111\u01b0\u1eddng xi\u00ean $NM$ v\u00e0 $NP$","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh \u0111\u1ed9 d\u00e0i hai h\u00ecnh chi\u1ebfu $KM$ v\u00e0 $KP$ <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh \u0111\u1ed9 d\u00e0i hai \u0111\u01b0\u1eddng xi\u00ean $NM$ v\u00e0 $NP$ <br\/> <b> B\u01b0\u1edbc 3:<\/b> So s\u00e1nh $\\widehat{NMP}$ v\u00e0 $\\widehat{NPM}$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong $\\triangle{MNP}$ <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D09.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> $IP > IM$ (gt) $\\Rightarrow$ $KP > KM$ (\u0111\u01b0\u1eddng xi\u00ean l\u1edbn h\u01a1n th\u00ec h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n) <br\/> V\u00ec $KP > KM$ n\u00ean $NP > NM$ (h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean l\u1edbn h\u01a1n) <br\/> $\\triangle{MNP}$ c\u00f3 $NP > NM$ n\u00ean $\\widehat{NMP} > \\widehat{NPM}$ (quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong m\u1ed9t tam gi\u00e1c) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span> ","column":3}]}],"id_ques":1840},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u \">\", \"<\" ho\u1eb7c \"=\" th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D10.png' \/><\/center> <br\/> Cho tam gi\u00e1c $ABC$ c\u00f3 $\\widehat{A} = 90^{o}$, $AB > AC$. \u0110\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n $BC$ c\u1eaft c\u1ea1nh $AB$ t\u1ea1i $D$, c\u1eaft $BC$ t\u1ea1i $E$. L\u1ea5y $M$ tr\u00ean c\u1ea1nh $AB$ sao cho $AM > AD$ <br\/> Khi \u0111\u00f3: $BD$ _input_ $CM$ ","hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh $DB$ v\u00e0 $DC$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh $DC$ v\u00e0 $CM$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu <br\/> <b> B\u01b0\u1edbc 3: <\/b> So s\u00e1nh $DB$ v\u00e0 $CM$ <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D10.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> $EB$ v\u00e0 $EC$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 h\u00ecnh chi\u1ebfu c\u1ee7a $DB$ v\u00e0 $DC$ tr\u00ean $BC$ <br\/> V\u00ec $EB = EC$ ($DE$ l\u00e0 trung tr\u1ef1c c\u1ee7a $BC$) <br\/> $\\Rightarrow$ $DB = DC$ (h\u00ecnh chi\u1ebfu b\u1eb1ng nhau th\u00ec \u0111\u01b0\u1eddng xi\u00ean b\u1eb1ng nhau) (1) <br\/> V\u00ec $\\widehat{A} = 90^{o}$ n\u00ean $AD$ v\u00e0 $AM$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 h\u00ecnh chi\u1ebfu c\u1ee7a $CD$ v\u00e0 $CM$ tr\u00ean $AB$ <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $AM > AD$ (gt) n\u00ean $CM > CD$ (h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean l\u1edbn h\u01a1n) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $CM > DB$ hay $DB < CM$ <br\/> <span class='basic_pink'> V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u: $<$ <\/span> "}]}],"id_ques":1841},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u \">\", \"<\" ho\u1eb7c \"=\" th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Cho tam gi\u00e1c $ABC$ nh\u1ecdn, \u0111i\u1ec3m $D$ n\u1eb1m gi\u1eefa $B$ v\u00e0 $C$ sao cho $AD$ kh\u00f4ng vu\u00f4ng g\u00f3c v\u1edbi $BC$. G\u1ecdi $H$ v\u00e0 $K$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 ch\u00e2n \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c k\u1ebb t\u1eeb $B$ v\u00e0 $C$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $AD$. <br\/> Khi \u0111\u00f3: $BH + CK$ _input_ $AB + AC$ ","hint":"So s\u00e1nh $BH$ v\u1edbi $AB$, $CK$ v\u1edbi $AC$","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh $AB$ v\u00e0 $BH$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh $AC$ v\u00e0 $CK$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean <br\/> <b> B\u01b0\u1edbc 3: <\/b> So s\u00e1nh $BH + CK$ v\u00e0 $AB + AC$ <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D11.png' \/><\/center> <br\/> Ta c\u00f3: <br\/>$BH \\perp AD$ (gt) <br\/> N\u00ean $BH < AB$ (\u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c ng\u1eafn h\u01a1n \u0111\u01b0\u1eddng xi\u00ean) (1) <br\/> $CK \\perp AD$ <br\/> N\u00ean $CK < AC$ (\u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c ng\u1eafn h\u01a1n \u0111\u01b0\u1eddng xi\u00ean) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $BH + CK < AB + AC$ <br\/> <span class='basic_pink'> V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u: $<$ <\/span> "}]}],"id_ques":1842},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u \">\", \"<\" ho\u1eb7c \"=\" th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[[">"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Cho tam gi\u00e1c $ABC$ nh\u1ecdn, \u0111i\u1ec3m $D$ n\u1eb1m gi\u1eefa $B$ v\u00e0 $C$ sao cho $AD$ kh\u00f4ng vu\u00f4ng g\u00f3c v\u1edbi $BC$. G\u1ecdi $H$ v\u00e0 $K$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 ch\u00e2n \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c k\u1ebb t\u1eeb $B$ v\u00e0 $C$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $AD$. <br\/> Khi \u0111\u00f3: $BC$ _input_ $BH + CK$ ","hint":"So s\u00e1nh $BH$ v\u1edbi $BD$, $CK$ v\u1edbi $CD$","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh $BH$ v\u00e0 $BD$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh $CK$ v\u00e0 $CD$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean <br\/> <b> B\u01b0\u1edbc 3: <\/b> So s\u00e1nh $BC$ v\u00e0 $BH + CK$ <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D11.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> $BH \\perp HD$ n\u00ean $BH < BD$ (\u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c ng\u1eafn h\u01a1n \u0111\u01b0\u1eddng xi\u00ean) <br\/> $CK \\perp DK$ n\u00ean $CK < CD$ (\u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c ng\u1eafn h\u01a1n \u0111\u01b0\u1eddng xi\u00ean) <br\/> Do \u0111\u00f3: $BH + CK < BD + CD = BC$ <br\/> <span class='basic_pink'> V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u: $>$ <\/span> "}]}],"id_ques":1843},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u \">\", \"<\" ho\u1eb7c \"=\" th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Cho tam gi\u00e1c $ABC$ c\u00f3 $\\widehat{A} = 90^{o}$, $AB < AC$. Tia ph\u00e2n gi\u00e1c c\u1ee7a $\\widehat{ABC}$ c\u1eaft $AC$ t\u1ea1i $D$. Qua $C$ v\u1ebd \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u1edbi $AC$, c\u1eaft \u0111\u01b0\u1eddng th\u1eb3ng $BD$ t\u1ea1i $E$ <br\/> Khi \u0111\u00f3: $AC$ _input_ $CE$ ","hint":"So s\u00e1nh qua c\u1ea1nh trung gian l\u00e0 $BC$","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh $BC$ v\u00e0 $CE$ b\u1eb1ng c\u00e1ch so s\u00e1nh $\\widehat{CBE}$ v\u00e0 $\\widehat{CEB}$ <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh $BC$ v\u00e0 $AC$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong tam gi\u00e1c <br\/> <b> B\u01b0\u1edbc 3: <\/b> So s\u00e1nh $AC$ v\u00e0 $CE$ <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D13.png' \/><\/center> <br\/> Ta c\u00f3: $AB \/\/ CE$ (c\u00f9ng vu\u00f4ng g\u00f3c v\u1edbi $AC$) n\u00ean $\\widehat{CEB} = \\widehat{ABE}$ (so le trong) <br\/> M\u00e0 $\\widehat{ABD} = \\widehat{CBD}$ n\u00ean $\\widehat{CBE} = \\widehat{CEB}$ <br\/> Do \u0111\u00f3 $\\triangle{CBE}$ c\u00e2n t\u1ea1i $C$ $\\Rightarrow$ $CB = CE$ (1) <br\/> X\u00e9t $\\triangle{ABC}$ c\u00f3 $\\widehat{A} = 90^{o}$ n\u00ean $BC > AC$ (quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $CE > AC$ hay $AC < CE$ <br\/> <span class='basic_pink'> V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u: $<$ <\/span> "}]}],"id_ques":1844},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Cho tam gi\u00e1c $MNP$ vu\u00f4ng t\u1ea1i $N$, \u0111i\u1ec3m $Q$ n\u1eb1m gi\u1eefa $N$ v\u00e0 $P$. K\u1ebft lu\u1eadn n\u00e0o sau \u0111\u00e2y l\u00e0 \u0111\u00fang? ","select":["A. $MQ > MN > MP $ ","B. $MN < MQ < MP $","C. $MP > MN > MQ $","D. $NP < NQ < MP $"],"hint":"","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D14.png' \/><\/center> <br\/> V\u00ec \u0111i\u1ec3m $Q$ n\u1eb1m gi\u1eefa hai \u0111i\u1ec3m $N$ v\u00e0 $P$ n\u00ean $NQ < NP$ <br\/> Do \u0111\u00f3 $MQ < MP$ (h\u00ecnh chi\u1ebfu nh\u1ecf h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean nh\u1ecf h\u01a1n) <br\/> M\u1eb7t kh\u00e1c ta c\u00f3 $MN \\perp NP$ (gt) <br\/> $\\Rightarrow$ $MN < MQ < MP$ (\u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c l\u00e0 \u0111\u01b0\u1eddng ng\u1eafn nh\u1ea5t) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B <\/span> ","column":2}]}],"id_ques":1845},{"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":"Cho tam gi\u00e1c $ABC$ vu\u00f4ng t\u1ea1i $A$, $E$ l\u00e0 \u0111i\u1ec3m b\u1ea5t k\u00ec tr\u00ean c\u1ea1nh $AC$ ($E$ kh\u00f4ng tr\u00f9ng v\u1edbi $A$ v\u00e0 $C$). Tr\u00ean tia \u0111\u1ed1i c\u1ee7a tia $AC$ l\u1ea5y \u0111i\u1ec3m $D$ sao cho $AE = AD$, n\u1ed1i $BD$. K\u1ebft lu\u1eadn n\u00e0o sau \u0111\u00e2y l\u00e0 \u0111\u00fang? ","select":["A. $BD < BC $ ","B. $BD = BC $","C. $BD > BC $"],"hint":"","explain":" <span class='basic_left'> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D15.png' \/><\/center> <br\/> Ta c\u00f3: <br\/> V\u00ec $E \\in AC$ ($E$ kh\u00e1c $A$ v\u00e0 $C$) n\u00ean $AE < AC$ (1) <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $AE = AD$ (gt) (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $AD < AC$ n\u00ean $BD < BC$ (h\u00ecnh chi\u1ebfu nh\u1ecf h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean nh\u1ecf h\u01a1n) <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span> ","column":3}]}],"id_ques":1846},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["t","t","f"]],"list":[{"point":5,"image":"","col_name":["Kh\u1eb3ng \u0111\u1ecbnh","\u0110\u00fang","Sai"],"arr_ques":[" T\u1eeb m\u1ed9t \u0111i\u1ec3m \u1edf ngo\u00e0i m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng ta ch\u1ec9 k\u1ebb \u0111\u01b0\u1ee3c duy nh\u1ea5t m\u1ed9t \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c xu\u1ed1ng \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3","Trong c\u00e1c \u0111\u01b0\u1eddng xi\u00ean v\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c k\u1ebb t\u1eeb m\u1ed9t \u0111i\u1ec3m \u1edf ngo\u00e0i m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3, \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c ng\u1eafn h\u01a1n m\u1ecdi \u0111\u01b0\u1eddng xi\u00ean "," N\u1ebfu hai \u0111i\u1ec3m c\u00f9ng m\u1ed9t h\u00ecnh chi\u1ebfu tr\u00ean m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng th\u00ec hai \u0111i\u1ec3m \u1ea5y tr\u00f9ng nhau"],"hint":"","explain":[" \u0110\u00daNG "," <br\/> \u0110\u00daNG theo \u0111\u1ecbnh l\u00fd v\u1ec1 m\u1ed1i quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u00e0 \u0111\u01b0\u1eddng xi\u00ean ","<br\/> SAI v\u00ec hai \u0111i\u1ec3m \u1ea5y c\u00f3 th\u1ec3 \u0111\u1ed1i x\u1ee9ng nhau qua \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3 <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D19.png' \/><\/center> "]}]}],"id_ques":1847},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["1"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Cho $\\widehat{xOy} = 45^{o}$. Tr\u00ean tia $Oy$ l\u1ea5y hai \u0111i\u1ec3m $A$, $B$ sao cho $AB = \\sqrt{2}$(cm) . T\u00ednh \u0111\u1ed9 d\u00e0i h\u00ecnh chi\u1ebfu c\u1ee7a \u0111o\u1ea1n th\u1eb3ng $AB$ tr\u00ean $Ox$. <br\/> \u0110\u00e1p \u00e1n l\u00e0: _input_ cm ","hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b>K\u1ebb $AH \\perp Ox$, $BK \\perp Ox$, $AI \\perp BK$ khi \u0111\u00f3 $HK = AI$ <br\/> <b> B\u01b0\u1edbc 2: <\/b> Ch\u1ee9ng minh $\\triangle{AIB}$ vu\u00f4ng c\u00e2n <br\/> <b> B\u01b0\u1edbc 3: <\/b> \u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00fd Pitago t\u00ednh \u0111\u1ed9 d\u00e0i $AI$ <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D16.png' \/><\/center> <br\/> K\u1ebb $AH \\perp Ox$, $BK \\perp Ox$ $(H, K \\in Ox)$ <br\/> Khi \u0111\u00f3 $HK$ l\u00e0 h\u00ecnh chi\u1ebfu c\u1ee7a $AB$ tr\u00ean $Ox$ <br\/> K\u1ebb $AI \\perp BK$ $\\Rightarrow$ $AI = HK$ (t\u00ednh ch\u1ea5t \u0111o\u1ea1n ch\u1eafn) <br\/> $\\triangle{OKB}$ vu\u00f4ng t\u1ea1i $K$ c\u00f3 $\\widehat{O} = 45^{o}$ <br\/> $\\Rightarrow$ $\\triangle{OKB}$ vu\u00f4ng c\u00e2n t\u1ea1i $K$ n\u00ean $\\widehat{B} = 45^{o}$ <br\/> $\\triangle{AIB}$ vu\u00f4ng t\u1ea1i $I$ c\u00f3 $\\widehat{B} = 45^{o}$ <br\/> $\\Rightarrow$ $\\triangle{AIB}$ vu\u00f4ng c\u00e2n t\u1ea1i $I$ <br\/> Suy ra $IA = IB$ <br\/> \u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00fd Pitago cho tam gi\u00e1c vu\u00f4ng $AIB$ ta c\u00f3: <br\/> $IA^{2} + IB^{2} = AB^{2}$ <br\/> $\\Leftrightarrow$ $2IA^{2} = (\\sqrt{2})^2$ <br\/> $\\Leftrightarrow IA^{2} = 1$ <br\/> $\\Rightarrow IA = 1 (cm)$ <br\/> $\\Rightarrow$ $HK = IA = 1(cm)$ <br\/> <span class='basic_pink'> V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0: 1 <\/span> "}]}],"id_ques":1848},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u \">\", \"<\" ho\u1eb7c \"=\" th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng ","title_trans":"","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":50,"type_input":"","ques":" Cho tam gi\u00e1c $ABC$ c\u00f3 $\\widehat{B} > \\widehat{C}$. G\u1ecdi $AH$ l\u00e0 \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c k\u1ebb t\u1eeb $A$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $BC$. G\u1ecdi $M$ l\u00e0 m\u1ed9t \u0111i\u1ec3m thu\u1ed9c \u0111o\u1ea1n th\u1eb3ng $AH$ ($M$ kh\u00e1c $A$ v\u00e0 $H$). So s\u00e1nh \u0111\u1ed9 d\u00e0i $MB$ v\u00e0 $MC$ <br\/> \u0110\u00e1p \u00e1n l\u00e0: $MB$ _input_ $MC$ ","hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh $AB$ v\u00e0 $AC$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong tam gi\u00e1c $ABC$ <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh $HB$ v\u00e0 $HC$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu <br\/> <b> B\u01b0\u1edbc 3: <\/b> So s\u00e1nh $MB$ v\u00e0 $MC$ d\u1ef1a v\u00e0o quan h\u1ec7 gi\u1eefa \u0111\u01b0\u1eddng xi\u00ean v\u00e0 h\u00ecnh chi\u1ebfu <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D17.png' \/><\/center> <br\/> X\u00e9t $\\triangle{ABC}$ c\u00f3 $\\widehat{B} > \\widehat{C}$ <br\/> $\\Rightarrow AC > AB$ (quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong $\\triangle{ABC}$) <br\/> Ta c\u00f3: $AH \\perp BC$ n\u00ean $HB, HC$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 h\u00ecnh chi\u1ebfu c\u1ee7a $AB, AC$ tr\u00ean $BC$ <br\/> V\u00ec $AC > AB$ $\\Rightarrow HC > HB$ (\u0111\u01b0\u1eddng xi\u00ean l\u1edbn h\u01a1n th\u00ec h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n) <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $HB$ v\u00e0 $HC$ c\u0169ng l\u00e0 h\u00ecnh chi\u1ebfu c\u1ee7a $MB$ v\u00e0 $MC$ tr\u00ean $BC$ <br\/> V\u00ec $HC > HB$ n\u00ean $MC > MB$ (h\u00ecnh chi\u1ebfu l\u1edbn h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean l\u1edbn h\u01a1n) <br\/> <span class='basic_pink'> V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u: $<$ <\/span> "}]}],"id_ques":1849},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Cho h\u00ecnh v\u1ebd, bi\u1ebft $AD = AB, AH \\perp BD$: <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D18.png' \/><\/center><br\/> Trong c\u00e1c kh\u1eb3ng \u0111\u1ecbnh sau, kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. $AB > AC$ ","B. $AB < AC$","C. $AB = AC$","D. M\u1ed9t k\u1ebft qu\u1ea3 kh\u00e1c"],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> So s\u00e1nh $AD$ v\u00e0 $AE$ d\u1ef1a v\u00e0o vi\u1ec7c so s\u00e1nh hai h\u00ecnh chi\u1ebfu <br\/> <b> B\u01b0\u1edbc 2: <\/b> So s\u00e1nh $AE$ v\u00e0 $AC$ sau \u0111\u00f3 so s\u00e1nh $AB$ v\u00e0 $AC$ <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop7/toan/hinhhoc/bai18/lv1/img\/H7C3B18_D18.png' \/><\/center> <br\/> Do $AH \\perp BD$ n\u00ean $HD$ v\u00e0 $HE$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 h\u00ecnh chi\u1ebfu c\u1ee7a $AD$ v\u00e0 $AE$ tr\u00ean $BE$ <br\/> V\u00ec $HD < HE$ n\u00ean $AD < AE$ (h\u00ecnh chi\u1ebfu nh\u1ecf h\u01a1n th\u00ec \u0111\u01b0\u1eddng xi\u00ean nh\u1ecf h\u01a1n) <br\/> M\u00e0 $AE < AC$ n\u00ean $AD < AC$ <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $AB = AD$ (gt), suy ra $AB < AC$ <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B <\/span> ","column":2}]}],"id_ques":1850}],"lesson":{"save":0,"level":1}}