{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["2"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho $PQ$ v\u00e0 $MN$ l\u00e0 hai d\u00e2y cung c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O).$ K\u1ebb $OH \\bot PQ$ t\u1ea1i $H, OK \\bot MN$ t\u1ea1i $K,$ bi\u1ebft r\u1eb1ng $MN = PQ, OK = 2 cm .$ \u0110\u1ed9 d\u00e0i c\u1ea1nh $OH $ l\u00e0 _input_ $(cm)$ <\/span>","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D11.jpg' \/><\/center><br\/> <span class='basic_left'> Ta c\u00f3: $OH \\bot PQ$ v\u00e0 $OK \\bot MN$ (gi\u1ea3 thi\u1ebft) <br\/> $\\Rightarrow$ Kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn $PQ$ v\u00e0 $MN$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 $OH$ v\u00e0 $OK$ <br\/> Do $MN = PQ$ (gi\u1ea3 thi\u1ebft) <br\/> $\\Rightarrow OH = OK $ (\u0111\u1ecbnh l\u00ed v\u1ec1 li\u00ean h\u1ec7 gi\u1eefa d\u00e2y v\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y) <br\/> $\\Rightarrow OH= 2\\,(cm)$ <br\/> <span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $2.$ <\/span> "}]}],"id_ques":1121},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["t","f","t"]],"list":[{"point":5,"col_name":["","\u0110\u00fang","Sai"],"arr_ques":["Trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n, hai d\u00e2y b\u1eb1ng nhau th\u00ec c\u00e1ch \u0111\u1ec1u t\u00e2m ","Hai d\u00e2y c\u00e1ch \u0111\u1ec1u t\u00e2m th\u00ec b\u1eb1ng nhau","Trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n, d\u00e2y l\u1edbn h\u01a1n th\u00ec g\u1ea7n t\u00e2m h\u01a1n"],"explain":["\u0110\u00fang, theo \u0111\u1ecbnh l\u00ed v\u1ec1 li\u00ean h\u1ec7 gi\u1eefa d\u00e2y v\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y <br\/>","Sai, v\u00ec hai d\u00e2y c\u00f3 th\u1ec3 \u1edf hai \u0111\u01b0\u1eddng tr\u00f2n kh\u00e1c nhau <br\/>","\u0110\u00fang, theo \u0111\u1ecbnh l\u00ed v\u1ec1 li\u00ean h\u1ec7 gi\u1eefa d\u00e2y v\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y"]}]}],"id_ques":1122},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["t","t","f","t"]],"list":[{"point":5,"ques":"Cho $AB$ v\u00e0 $CD$ l\u00e0 hai d\u00e2y (kh\u00e1c \u0111\u01b0\u1eddng k\u00ednh) c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O; R).$ G\u1ecdi $OH$ v\u00e0 $OK$ theo th\u1ee9 t\u1ef1 l\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn $AB$ v\u00e0 $CD$","col_name":["","\u0110\u00fang","Sai"],"arr_ques":["N\u1ebfu $AB = CD$ th\u00ec $OH = OK$ ","N\u1ebfu $OH = OK$ th\u00ec $AB = CD$","N\u1ebfu $AB < CD$ th\u00ec $OH < OK$","N\u1ebfu $AB > CD$ th\u00ec $OH < OK$"],"explain":["\u0110\u00fang, v\u00ec trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n hai d\u00e2y b\u1eb1ng nhau th\u00ec c\u00e1ch \u0111\u1ec1u t\u00e2m.","\u0110\u00fang, v\u00ec trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n hai d\u00e2y c\u00e1ch \u0111\u1ec1u t\u00e2m th\u00ec b\u1eb1ng nhau","Sai, v\u00ec n\u1ebfu $AB < CD$ th\u00ec $OH > OK$ ","\u0110\u00fang, v\u00ec trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n d\u00e2y n\u00e0o l\u1edbn h\u01a1n th\u00ec g\u1ea7n t\u00e2m h\u01a1n"]}]}],"id_ques":1123},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho ba c\u00e2u","temp":"fill_the_blank","correct":[[["4"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$ c\u00f3 b\u00e1n k\u00ednh $5 cm,$ \u0111\u1ed9 d\u00e0i d\u00e2y $AB = 6 cm.$ V\u1ebd d\u00e2y $CD$ song song v\u1edbi $AB$ c\u00f3 \u0111\u1ed9 d\u00e0i l\u00e0 $8 cm .$ <br\/><b> C\u00e2u 1: <\/b> Kho\u1ea3ng c\u00e1ch t\u1eeb \u0111i\u1ec3m $O$ \u0111\u1ebfn $AB $_input_ $(cm)$ <\/span>","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D9.jpg' \/><\/center><br\/><span class='basic_left'> K\u1ebb $OH \\bot AB $ <br\/> $\\Rightarrow H$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $AB$ (\u0111\u1ecbnh l\u00ed quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) <br\/> $\\Rightarrow AH = HB=\\dfrac{AB}{2}=3\\,(cm)$ <br\/> X\u00e9t $\\Delta AHO$ vu\u00f4ng t\u1ea1i $H$ c\u00f3: <br\/> $AO^2=OH^2+HA^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $\\Rightarrow OH^2= 5^2-3^2 \\\\ \\Rightarrow OH^2= 16 \\\\ \\Rightarrow OH = 4\\,(cm)$ <br\/> Suy ra kho\u1ea3ng c\u00e1ch t\u1eeb \u0111i\u1ec3m $O$ \u0111\u1ebfn $AB$ l\u00e0 $ 4\\, cm$ <br\/> <span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $4.$ <\/span> "}]}],"id_ques":1124},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho ba c\u00e2u","temp":"fill_the_blank","correct":[[["3"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$ c\u00f3 b\u00e1n k\u00ednh $5 cm,$ d\u00e2y $AB = 6 cm.$ V\u1ebd d\u00e2y CD song song v\u1edbi AB c\u00f3 \u0111\u1ed9 d\u00e0i l\u00e0 $8 cm.$ <br\/><b> C\u00e2u 2: <\/b> Kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn $CD =$_input_ $(cm)$ <\/span>","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D8.jpg' \/><\/center><br\/> <span class='basic_left'> K\u1ebb $OK \\bot CD$ <br\/> $\\Rightarrow K$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $CD$ (\u0111\u1ecbnh l\u00ed quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) <br\/> $\\Rightarrow CK = KD=\\dfrac{CD}{2}=4\\,(cm)$ <br\/> X\u00e9t $\\Delta DKO$ vu\u00f4ng t\u1ea1i $K$ c\u00f3: <br\/> $DO^2=OK^2+KD^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $\\Rightarrow OK^2= 5^2-4^2\\\\ \\Rightarrow OK^2= 9\\\\ \\Rightarrow OK = 3\\,(cm)$ <br\/> Suy ra kho\u1ea3ng c\u00e1ch t\u1eeb \u0111i\u1ec3m $O$ \u0111\u1ebfn $CD$ l\u00e0 $ 3 \\,cm$ <br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $3.$ <\/span> "}]}],"id_ques":1125},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho ba c\u00e2u","temp":"fill_the_blank","correct":[[["49"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$ c\u00f3 b\u00e1n k\u00ednh $5 cm,$ d\u00e2y $AB = 6 cm.$ V\u1ebd d\u00e2y $CD$ song song v\u1edbi $AB$ c\u00f3 \u0111\u1ed9 d\u00e0i l\u00e0 $8 cm$ <br\/><b> C\u00e2u 3: <\/b> Di\u1ec7n t\u00edch h\u00ecnh thang $ABCD$ l\u00e0 _input_$cm^2$<\/span>","explain":"<span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_8.jpg' \/><\/center><br\/>V\u00ec $AB \/\/ CD,$ $OH \\bot AB,$ $OK \\bot CD$ <br\/>Suy ra ba \u0111i\u1ec3m $O, H, K$ th\u1eb3ng h\u00e0ng <br\/> $\\Rightarrow HK = OH + HK $ $=4+3= 7\\,(cm)$ <br\/> Di\u1ec7n t\u00edch h\u00ecnh thang $ABCD $ l\u00e0: <br\/> $S = \\dfrac{(AB+CD).HK}{2}$ $=\\dfrac{(6+8).7}{2}=49\\,(cm^2)$ <br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $49.$ <\/span> <\/span>"}]}],"id_ques":1126},{"time":24,"part":[{"title":"Ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"select":["A. $\\sqrt{2}$","B. $2\\sqrt{2}$","C. $3\\sqrt{2}$"],"ques":"Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$, b\u00e1n k\u00ednh $3 cm$ v\u00e0 d\u00e2y cung $AB =2 cm.$ <br\/>Kho\u1ea3ng c\u00e1ch t\u1eeb \u0111i\u1ec3m $O$ \u0111\u1ebfn $AB$ l\u00e0 ?$(cm)$","hint":"K\u1ebb $OH \\bot AB$ ","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D5.jpg' \/><\/center><br\/> <span class='basic_left'> K\u1ebb $OH \\bot AB$ t\u1ea1i $H$ <br\/> $\\Rightarrow H$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $AB$ (\u0111\u1ecbnh l\u00ed quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) <br\/> $\\Rightarrow AH = HB =\\dfrac{AB}{2}=1\\,(cm)$ <br\/> X\u00e9t $\\Delta AOH$ vu\u00f4ng t\u1ea1i $H$ c\u00f3: <br\/> $OA^2=OH^2+AH^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $\\Rightarrow OH^2= 3^2-1^2\\\\ \\Rightarrow OH^2=8\\\\ \\Rightarrow OH =2\\sqrt{2}\\,(cm)$"}]}],"id_ques":1127},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u > , < , = th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["="]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"Cho \u0111\u01b0\u1eddng tr\u00f2n $(O),$ hai d\u00e2y $PQ, RS.$ H\u1ea1 $OH \\bot PQ,$ $OK \\bot RS.$ <br\/> Ta c\u00f3 $OH = OK \\Leftrightarrow PQ $ _input_$RS$","explain":"Theo \u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y th\u00ec $OH = OK \\Leftrightarrow PQ = RS$ <br\/><span class='basic_pink'> V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u =<\/span>"}]}],"id_ques":1128},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn c\u1ee5m t\u1eeb th\u00edch h\u1ee3p \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"Trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n, hai d\u00e2y . . . th\u00ec c\u00e1ch \u0111\u1ec1u ...","select":["A. B\u1eb1ng nhau, t\u00e2m","B. C\u1eaft nhau, t\u00e2m","C. Vu\u00f4ng g\u00f3c, t\u00e2m"],"explain":" Trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n, hai d\u00e2y b\u1eb1ng nhau th\u00ec c\u00e1ch \u0111\u1ec1u t\u00e2m <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A.<\/span>","column":3}]}],"id_ques":1129},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["f","t","t","t"]],"list":[{"point":5,"ques":"Cho $EF$ v\u00e0 $IK$ l\u00e0 hai d\u00e2y (kh\u00e1c \u0111\u01b0\u1eddng k\u00ednh) c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O; R).$ G\u1ecdi $OA$ v\u00e0 $OB$ theo th\u1ee9 t\u1ef1 l\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn $EF$ v\u00e0 $IK$","col_name":["","\u0110\u00fang","Sai"],"arr_ques":["N\u1ebfu $EF > IK$ th\u00ec $OA > OB$ ","N\u1ebfu $EF = IK$ th\u00ec $OA = OB$","N\u1ebfu $EF < IK$ th\u00ec $OA > OB$","N\u1ebfu $OA = OB$ th\u00ec $EF = IK$ "],"explain":["Sai, v\u00ec d\u00e2y n\u00e0o l\u1edbn h\u01a1n th\u00ec g\u1ea7n t\u00e2m h\u01a1n <br\/> $\\Rightarrow$ N\u1ebfu $EF > IK$ th\u00ec $OA < OB$ <br\/>","\u0110\u00fang, do trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n hai d\u00e2y b\u1eb1ng nhau th\u00ec c\u00e1ch \u0111\u1ec1u t\u00e2m<br\/>","\u0110\u00fang, do trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n d\u00e2y n\u00e0o l\u1edbn h\u01a1n th\u00ec g\u1ea7n t\u00e2m h\u01a1n <br\/>","\u0110\u00fang, do trong m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n hai d\u00e2y c\u00e1ch \u0111\u1ec1u t\u00e2m th\u00ec b\u1eb1ng nhau"]}]}],"id_ques":1130},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Cho tam gi\u00e1c $ABC$ c\u00e2n t\u1ea1i $A$ v\u00e0 n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n $(O).$ G\u1ecdi $OP, OE, OF$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn $AB, AC, BC.$ Ta c\u00f3 ","select":["A. $OP = OE = OF$","B. $OP = OE$","C. $OE = OF$","D. $OE = OF$"],"explain":"<br\/><span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/h922_1.png' \/><\/center> $\\Delta ABC$ c\u00e2n t\u1ea1i $A$ (gi\u1ea3 thi\u1ebft) $\\Rightarrow AB = AC$ (t\u00ednh ch\u1ea5t tam gi\u00e1c c\u00e2n) <br\/> Suy ra $OP = OE$ (\u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y) <br\/> T\u01b0\u01a1ng t\u1ef1: Do $BC \\ne AB$ v\u00e0 $BC \\ne AC$ n\u00ean c\u00e1c m\u1ec7nh \u0111\u1ec1 $OE = OF$ v\u00e0 $OP = OF$ l\u00e0 sai <br\/> $\\Rightarrow OP = OE = OF$ c\u0169ng l\u00e0 m\u1ed9t m\u1ec7nh \u0111\u1ec1 kh\u00f4ng \u0111\u00fang<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span>","column":2}]}],"id_ques":1131},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u > , < , = th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"fill_the_blank","correct":[[["<"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"Cho h\u00ecnh 1 trong \u0111\u00f3 hai \u0111\u01b0\u1eddng trong c\u00f9ng c\u00f3 t\u00e2m $O$. Cho bi\u1ebft $AB > AC.$ <br\/><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D2.jpg' \/><\/center> <br\/> <b> C\u00e2u 1:<\/b> So s\u00e1nh $OH$ v\u00e0 $OK$ <br\/> <b> \u0110\u00e1p s\u1ed1: <\/b> $OH$ _input_ $OK$","hint":"Trong hai d\u00e2y c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n, d\u00e2y n\u00e0o l\u1edbn h\u01a1n th\u00ec d\u00e2y \u0111\u00f3 g\u1ea7n t\u00e2m h\u01a1n","explain":"<span class='basic_left'> X\u00e9t \u0111\u01b0\u1eddng tr\u00f2n l\u1edbn, Theo \u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y <br\/> $AB > AC \\Rightarrow OH < OK$ <br\/><span class='basic_pink'>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u < <\/span> "}]}],"id_ques":1132},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u > , < , = th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"fill_the_blank","correct":[[[">"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'> Cho h\u00ecnh 1 trong \u0111\u00f3 hai \u0111\u01b0\u1eddng trong c\u00f9ng c\u00f3 t\u00e2m $O$. <br\/> <center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D2.jpg' \/><\/center> <br\/><b> C\u00e2u 2:<\/b> Cho bi\u1ebft $AB > AC.$ H\u00e3y so s\u00e1nh $HM$ v\u00e0 $DK$ <br\/> <b> \u0110\u00e1p s\u1ed1: <\/b> $HM$ _input_ $DK$","explain":"<span class='basic_left'>X\u00e9t \u0111\u01b0\u1eddng tr\u00f2n nh\u1ecf, ta c\u00f3: $OH < OK$ (theo c\u00e2u 1) (1)<br\/> $\\Rightarrow EM > DF$ (\u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y) <br\/> M\u00e0 $OH \\bot EM$ <br\/> $\\Rightarrow HE=HM=\\dfrac{EM}{2}$ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) (2) <br\/> $OK \\bot DF$ <br\/> $\\Rightarrow FK= KD=\\dfrac{DF}{2}$ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) (3) <br\/> T\u1eeb (1), (2), (3) suy ra $HM > DK$ <br\/><span class='basic_pink'>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u > <\/span><\/span> "}]}],"id_ques":1133},{"time":24,"part":[{"title":"\u0110i\u1ec1n d\u1ea5u > , < , = th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[[">"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"Cho \u0111\u01b0\u1eddng tr\u00f2n $(O),$ hai d\u00e2y $PQ, RS.$ H\u1ea1 $OH \\bot PQ,$ $OK \\bot RS.$ <br\/>Ta c\u00f3 $OH < OK$ $\\Leftrightarrow PQ$ _input_$RS$ ","explain":"Theo \u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y <br\/> $ OH < OK \\Leftrightarrow PQ > RS$ <br\/><span class='basic_pink'>V\u1eady d\u1ea5u c\u1ea7n \u0111i\u1ec1n l\u00e0 d\u1ea5u > <\/span>"}]}],"id_ques":1134},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Cho tam gi\u00e1c $ABC$ n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n $(O).$ G\u1ecdi $OM, ON, OP$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn $BC, AC, AB$ v\u00e0 c\u00f3 $OM < ON < OP.$ So s\u00e1nh $AB, AC, BC$","select":["A. $ AC > AB > BC $","B. $ AB < BC < AC $","C. $ BC > AC > AB $","D. $ BC < AC < AB $"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D1.1.jpg' \/><\/center><span class='basic_left'> Ta c\u00f3: $OM < ON < OP $ (gi\u1ea3 thi\u1ebft) <br\/> $ \\Rightarrow BC > AC > AB$ (\u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y) <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span>","column":2}]}],"id_ques":1135},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"Ch\u1ecdn c\u1ee5m t\u1eeb th\u00edch h\u1ee3p \u0111i\u1ec1n v\u00e0o ch\u1ed7 tr\u1ed1ng","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Trong hai d\u00e2y c\u1ee7a m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n, d\u00e2y n\u00e0o l\u1edbn h\u01a1n th\u00ec . . .","select":["A. C\u00e1ch \u0111\u1ec1u t\u00e2m","B. D\u00e2y \u0111\u00f3 g\u1ea7n t\u00e2m h\u01a1n","C. D\u00e2y \u0111\u00f3 xa t\u00e2m h\u01a1n"],"explain":" Trong hai d\u00e2y c\u1ee7a m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n, d\u00e2y n\u00e0o l\u1edbn h\u01a1n th\u00ec g\u1ea7n t\u00e2m h\u01a1n <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B<\/span>","column":3}]}],"id_ques":1136},{"time":24,"part":[{"title":"Kh\u1eb3ng \u0111\u1ecbnh sau \u0110\u00fang hay Sai","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Cho \u0111\u01b0\u1eddng tr\u00f2n $(O; 1,5 cm)$ v\u00e0 d\u00e2y $AB$ di \u0111\u1ed9ng sao cho $AB = 2,4 cm.$ Khi \u0111\u00f3, trung \u0111i\u1ec3m $M$ c\u1ee7a $AB$ di \u0111\u1ed9ng tr\u00ean \u0111\u01b0\u1eddng tr\u00f2n $(O; 0,81 cm)$","select":["A. \u0110\u00fang","B. Sai"],"hint":"\u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00ed Pitago \u0111\u1ec3 t\u00ednh $OM$","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D4.jpg' \/><\/center><br\/><span class='basic_left'> Ta c\u00f3: $M$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $AB$ <br\/> $\\Rightarrow AM = MB= \\dfrac{AB}{2} = 1,2 \\, (cm)$ <br\/> $\\Rightarrow OM \\bot AB$ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y cung) <br\/> X\u00e9t $\\Delta AOM$ vu\u00f4ng t\u1ea1i $M$ c\u00f3: <br\/> $OA^2=OM^2+AM^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $\\Rightarrow OM^2=1,5^2 - 1,2^2 \\\\ \\Rightarrow OM^2=0,81\\\\ \\Rightarrow OM =0,9\\, (cm) $<br\/> Suy ra trung \u0111i\u1ec3m $M$ c\u1ee7a $AB$ di \u0111\u1ed9ng tr\u00ean \u0111\u01b0\u1eddng tr\u00f2n $(O; 0,9 cm)$ <br\/>V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 Sai <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span> ","column":2}]}],"id_ques":1137},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"","temp":"true_false","correct":[["t","t","f"]],"list":[{"point":5,"ques":"Cho tam gi\u00e1c $ABC$ n\u1ed9i ti\u1ebfp \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u00f3 $\\widehat{A}<\\widehat{B}<\\widehat{C}<90^o$. G\u1ecdi $M, N, P$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 trung \u0111i\u1ec3m c\u1ee7a c\u1ea1nh $BC, CA, AB.$ Khi \u0111\u00f3","col_name":["","\u0110\u00fang","Sai"],"arr_ques":["$cos \\widehat{A} > cos \\widehat{B} > cos \\widehat{C} $","$BC < AC < AB$","$OM < ON < OP$"],"explain":["\u0110\u00fang, v\u00ec trong c\u00e1c g\u00f3c nh\u1ecdn, g\u00f3c n\u00e0o nh\u1ecf h\u01a1n th\u00ec gi\u00e1 tr\u1ecb c\u00f4sin c\u1ee7a n\u00f3 l\u1edbn h\u01a1n","\u0110\u00fang v\u00ec $\\widehat{A}<\\widehat{B}<\\widehat{C}$ (gi\u1ea3 thi\u1ebft) <br\/> $\\Rightarrow BC < AC < AB$ (quan h\u1ec7 gi\u1eefa g\u00f3c v\u00e0 c\u1ea1nh \u0111\u1ed1i di\u1ec7n trong m\u1ed9t tam gi\u00e1c)"," Sai, Ta c\u00f3 $OM \\bot BC,$ $ON \\bot CA,$ $OP \\bot AB.$ <br\/> $\\Rightarrow$ kho\u1ea3ng c\u00e1ch t\u1eeb c\u00e1c c\u1ea1nh $BC, CA, AB$ \u0111\u1ebfn t\u00e2m l\u1ea7n l\u01b0\u1ee3t l\u00e0 $OM, ON, OP$ <br\/> Do $ BC < AC < AB$ (ch\u1ee9ng minh tr\u00ean) <br\/> Suy ra $OM > ON > OP$ (\u0111\u1ecbnh l\u00ed v\u1ec1 kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m \u0111\u1ebfn d\u00e2y)"]}]}],"id_ques":1138},{"time":24,"part":[{"title":"\u0110i\u1ec1n k\u1ebft qu\u1ea3 th\u00edch h\u1ee3p v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"fill_the_blank","correct":[[["3"],["7"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$, hai d\u00e2y $AB$ v\u00e0 $CD$ vu\u00f4ng g\u00f3c v\u1edbi nhau \u1edf $M.$ Bi\u1ebft $AB = 20 cm ,$ $CD = 16 cm,$ $MA = 3 cm$ v\u00e0 $MC = 5 cm.$ <br\/><b> C\u00e2u 1:<\/b> T\u00ednh kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn m\u1ed7i d\u00e2y.<br\/><b> \u0110\u00e1p s\u1ed1: <\/b> Kho\u1ea3ng c\u00e1ch t\u1eeb $O$ \u0111\u1ebfn c\u00e1c d\u00e2y $AB$ v\u00e0 $CD$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 _input_ $(cm)$ v\u00e0 _input_ $(cm)$ <\/span>","explain":"<span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D3.jpg' \/><\/center><br\/><span class='basic_left'> K\u1ebb $OH \\bot CD$ <br\/> $\\Rightarrow HC= HD=\\dfrac{CD}{2}=8\\,(cm)$ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) <br\/> K\u1ebb $OK \\bot AB$ <br\/> $\\Rightarrow KA= KB=\\dfrac{AB}{2}=10\\,(cm)$ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y) <br\/> $MH = HC - MC = 8 - 5 = 3\\, (cm)$ <br\/> $MK = KA - MA = 10 - 3 = 7\\, (cm)$ <br\/> T\u1ee9 gi\u00e1c $OHMK$ l\u00e0 h\u00ecnh ch\u1eef nh\u1eadt ($\\widehat{M}=\\widehat{H}=\\widehat{K}={{90}^{o}}$) <br\/> Suy ra $OH = MK = 7\\, cm,$ $OK = MH = 3\\, cm$ <br\/> V\u1eady kho\u1ea3ng c\u00e1c t\u1eeb $O$ \u0111\u1ebfn c\u00e1c d\u00e2y $AB$ v\u00e0 $CD$ l\u1ea7n l\u01b0\u1ee3t l\u00e0 $3 cm$ v\u00e0 $7 cm$ <br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $3$ v\u00e0 $7.$<\/span> <\/span>"}]}],"id_ques":1139},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"\u0110\u1ec1 chung cho hai c\u00e2u","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$, hai d\u00e2y $AB$ v\u00e0 $CD$ vu\u00f4ng g\u00f3c v\u1edbi nhau \u1edf $M.$ Bi\u1ebft $AB = 20 cm ,$ $CD = 16 cm,$ $MA = 3 cm$ v\u00e0 $MC = 5 cm.$ <br\/><b> C\u00e2u 2:<\/b> B\u00e1n k\u00ednh \u0111\u01b0\u1eddng tr\u00f2n $(O)$ l\u00e0:<\/span>","select":["A. $\\sqrt{149}\\, cm$","B. $\\sqrt{91}\\, cm$","C. $3\\sqrt{11}\\, cm$","D. $\\sqrt{109}\\, cm$"],"hint":"\u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00ed Pitago \u0111\u1ec3 t\u00ednh c\u1ea1nh $AO$","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai7/lv1/img\/H922_D3.jpg' \/><\/center><br\/><span class='basic_left'> X\u00e9t $\\Delta AOK$ vu\u00f4ng t\u1ea1i $K$ c\u00f3: <br\/> $OA^2=AK^2+OK^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $\\Rightarrow OA^2=10^2+3^2\\\\ \\Rightarrow OA^2= 100 + 9 = 109\\\\ \\Rightarrow OA= \\sqrt{109}\\,(cm)$<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D.<\/span> ","column":4}]}],"id_ques":1140}],"lesson":{"save":0,"level":1}}