{"segment":[{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<span class='basic_left'>G\u1ecdi $d$ l\u00e0 kho\u1ea3ng c\u00e1ch t\u1eeb \u0111\u01b0\u1eddng th\u1eb3ng $a$ \u0111\u1ebfn t\u00e2m \u0111\u01b0\u1eddng tr\u00f2n $(O; R)$ <\/span>","select":["A. N\u1ebfu \u0111\u01b0\u1eddng th\u1eb3ng $a$ v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u1eaft nhau th\u00ec $d > R$","B. N\u1ebfu \u0111\u01b0\u1eddng th\u1eb3ng $a$ v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u1eaft nhau th\u00ec $d = R$","C. N\u1ebfu \u0111\u01b0\u1eddng th\u1eb3ng $a$ v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u1eaft nhau th\u00ec $d < R$"],"explain":"N\u1ebfu \u0111\u01b0\u1eddng th\u1eb3ng $a$ v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u1eaft nhau th\u00ec $d < R$ <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span>","column":1}]}],"id_ques":1151},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<span class='basic_left'>Cho \u0111i\u1ec3m $P$ thu\u1ed9c \u0111\u01b0\u1eddng tr\u00f2n $(O; R)$ . V\u1ebd ti\u1ebfp tuy\u1ebfn $Px$ v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i $M.$ Tr\u00ean $Px$ l\u1ea5y \u0111i\u1ec3m $Q$ sao cho $\\widehat{POQ}=45^o$. <br\/> T\u00ednh \u0111\u1ed9 d\u00e0i \u0111o\u1ea1n th\u1eb3ng $PQ$ theo $R$<\/span>","select":["A. $PQ = 2R$","B. $PQ = R$","C. $PQ = R\\sqrt{2}$","D. $PQ = R\\sqrt{3}$"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D24.jpg' \/><\/center> <span class='basic_left'> $PQ$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ <br\/> $\\Rightarrow PQ \\bot OP $ (theo t\u00ednh ch\u1ea5t ti\u1ebfp tuy\u1ebfn) <br\/>X\u00e9t $\\Delta OPQ$ vu\u00f4ng t\u1ea1i $P $ <br\/> $\\Rightarrow PQ = OP.tg \\widehat{POQ}$ (h\u1ec7 th\u1ee9c gi\u1eefa c\u1ea1nh v\u00e0 g\u00f3c trong tam gi\u00e1c vu\u00f4ng) <br\/> $ =R.tg 45^o\\\\ =R$ <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span>","column":4}]}],"id_ques":1152},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<span class='basic_left'>Tr\u00ean m\u1eb7t ph\u1eb3ng t\u1ecda \u0111\u1ed9 $Oxy,$ cho \u0111i\u1ec3m $I (4 ; 2).$ H\u00e3y x\u00e1c \u0111\u1ecbnh v\u1ecb tr\u00ed t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(I; 2)$ v\u1edbi tr\u1ee5c $Oy$ <\/span>","select":["A. \u0110\u01b0\u1eddng tr\u00f2n $(I; 2)$ ti\u1ebfp x\u00fac v\u1edbi tr\u1ee5c $Oy$","B. \u0110\u01b0\u1eddng tr\u00f2n $(I; 2)$ v\u00e0 tr\u1ee5c $Oy$ kh\u00f4ng giao nhau","C. \u0110\u01b0\u1eddng tr\u00f2n $(I; 2)$ v\u00e0 tr\u1ee5c $Oy$ c\u1eaft nhau","D. Ch\u01b0a x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923.jpg' \/><\/center>Kho\u1ea3ng c\u00e1ch t\u1eeb $I$ tr\u00ean tr\u1ee5c $Oy$ l\u00e0 $4$ <br\/> V\u1eady \u0111\u01b0\u1eddng tr\u00f2n $(I; 2)$ v\u00e0 tr\u1ee5c $Oy$ kh\u00f4ng giao nhau <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span>","column":2}]}],"id_ques":1153},{"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":[[["30"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'> Cho \u0111\u01b0\u1eddng tr\u00f2n $(O; R)$ , $M$ l\u00e0 m\u1ed9t \u0111i\u1ec3m sao cho $OM =2R.$ V\u1ebd ti\u1ebfp tuy\u1ebfn $MN$ c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ ($N$ l\u00e0 ti\u1ebfp \u0111i\u1ec3m). S\u1ed1 \u0111o g\u00f3c $OMN$ l\u00e0 _input_ $^o$ <\/span>","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D20.jpg' \/><\/center><br\/><span class='basic_left'> $MN$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ (theo t\u00ednh ch\u1ea5t ti\u1ebfp tuy\u1ebfn) <br\/> $\\Rightarrow MN \\bot ON$ <br\/> X\u00e9t $\\Delta OMN$ vu\u00f4ng t\u1ea1i $N$ <br\/> $\\Rightarrow \\sin \\widehat{OMN}=\\dfrac{ON}{OM}=\\dfrac{1}{2}\\\\ \\Rightarrow \\widehat{OMN}=30^o$ <br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $30.$ <\/span>"}]}],"id_ques":1154},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$ ngo\u1ea1i ti\u1ebfp tam gi\u00e1c $ABC$ vu\u00f4ng t\u1ea1i $A.$ Ti\u1ebfp tuy\u1ebfn \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i $A$ l\u00e0 \u0111\u01b0\u1eddng th\u1eb3ng:<\/span>","select":["A. \u0110i qua $A$ v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi $OB$","B. \u0110i qua $A$ v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi $OC$","C. \u0110i qua $A$ v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi $OA$ ","D. \u0110i qua $A$ v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi $AB$"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923.D1.2.jpg' \/><\/center>\u0110\u01b0\u1eddng tr\u00f2n t\u00e2m $O$ ngo\u1ea1i ti\u1ebfp tam gi\u00e1c $ABC$ vu\u00f4ng t\u1ea1i $A$ <br\/> Ti\u1ebfp tuy\u1ebfn \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i $A$ l\u00e0 \u0111\u01b0\u1eddng th\u1eb3ng \u0111i qua $A$ v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi $OA$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span>","column":2}]}],"id_ques":1155},{"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":[[["10"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n $(O; 6 cm)$ v\u00e0 \u0111i\u1ec3m $A$ tr\u00ean \u0111\u01b0\u1eddng tr\u00f2n. Qua $A$ k\u1ebb ti\u1ebfp tuy\u1ebfn $Ax,$ tr\u00ean \u0111\u00f3 l\u1ea5y \u0111i\u1ec3m $B$ sao cho $AB = 8 cm.$ <br\/><b> C\u00e2u 1: <\/b>\u0110\u1ed9 d\u00e0i c\u1ea1nh $OB$ l\u00e0_input_ cm <\/span>","hint":"\u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00ed Pitago","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D19.jpg' \/><\/center><br\/> <span class='basic_left'> $AB$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i $A$ n\u00ean $AB \\bot AO.$ <br\/>X\u00e9t $\\Delta AOB$ vu\u00f4ng t\u1ea1i $A$ <br\/> \u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00ed Pitago ta c\u00f3: <br\/> $OB^2=OA^2+AB^2\\\\ \\Rightarrow OB^2=6^2+8^2\\\\ \\Rightarrow OB^2=100 $ <br\/> $\\Rightarrow OB = 10\\,(cm)$ <br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $10.$ <\/span>"}]}],"id_ques":1156},{"time":24,"part":[{"title":"Kh\u1eb3ng \u0111\u1ecbnh sau \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 \u0111\u01b0\u1eddng tr\u00f2n $(O; 6 cm)$ v\u00e0 \u0111i\u1ec3m $A$ tr\u00ean \u0111\u01b0\u1eddng tr\u00f2n. Qua $A$ k\u1ebb ti\u1ebfp tuy\u1ebfn $Ax,$ tr\u00ean \u0111\u00f3 l\u1ea5y \u0111i\u1ec3m $B$ sao cho $AB = 8 cm.$ <br\/><b> C\u00e2u 2: <\/b> Qua $A$ k\u1ebb \u0111\u01b0\u1eddng th\u1eb3ng vu\u00f4ng g\u00f3c v\u1edbi $OB,$ c\u1eaft \u0111\u01b0\u1eddng tr\u00f2n $(O)$ \u1edf $C.$ <br\/>Khi \u0111\u00f3 $BC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ <\/span>","select":["A. \u0110\u00fang","B. Sai"],"explain":"<span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D18.jpg' \/><\/center><br\/>Ta c\u00f3: $OA = OC = 6 cm$<br\/> $\\Rightarrow\\Delta OAC$ c\u00e2n t\u1ea1i $O$ (\u0111\u1ecbnh ngh\u0129a) <br\/> M\u00e0 $OB \\bot AC$ (gi\u1ea3 thi\u1ebft) $\\Rightarrow \\widehat{O_{1}}=\\widehat{O_{2}}$ (t\u00ednh ch\u1ea5t tam gi\u00e1c c\u00e2n) <br\/> X\u00e9t $\\Delta OAB$ v\u00e0 $\\Delta OCB $ c\u00f3: <br\/> $OA = OC$ <br\/> $\\widehat{O_{1}}=\\widehat{O_{2}}$ <br\/> $OB$ chung <br\/>$\\Rightarrow \\Delta OAB=\\Delta OCB \\,\\,(c.g.c)$ <br\/> $\\Rightarrow \\widehat{OAB}=\\widehat{OCB}=90^o$ (hai g\u00f3c t\u01b0\u01a1ng \u1ee9ng) <br\/> Suy ra $BC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ <br\/> V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 \u0111\u00fang <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A.<\/span><\/span>","column":2}]}],"id_ques":1157},{"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":"<table> <tr> <th>V\u1ecb tr\u00ed tr\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a \u0111\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n<\/th> <th>H\u1ec7 th\u1ee9c $d$ v\u00e0 $R$<\/th> <\/tr> <tr> <td>\u0110\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n c\u1eaft nhau<\/td> <td>$d$ _input_ $R$<\/td> <\/tr> <tr> <td>\u0110\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n ti\u1ebfp x\u00fac nhau<\/td> <td>$d$ _input_ $R$<\/td> <\/tr> <tr> <td>\u0110\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n kh\u00f4ng giao nhau<\/td> <td>$d$ _input_ $R$<\/td> <\/tr><\/table>","explain":"<table> <tr> <th>V\u1ecb tr\u00ed tr\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a \u0111\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n<\/th> <th>H\u1ec7 th\u1ee9c $d$ v\u00e0 $R$<\/th> <\/tr> <tr> <td>\u0110\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n c\u1eaft nhau<\/td> <td>$d < R$<\/td> <\/tr> <tr> <td>\u0110\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n ti\u1ebfp x\u00fac nhau<\/td> <td> $d = R$<\/td> <\/tr> <tr> <td>\u0110\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n kh\u00f4ng giao nhau<\/td> <td>$d > R$<\/td> <\/tr><\/table>"}]}],"id_ques":1158},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","title_trans":"L\u1ef1a ch\u1ecdn \u0111\u00fang hay sai","temp":"true_false","correct":[["t","t","f","t"]],"list":[{"point":10,"image":"https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D15.jpg","col_name":["Cho tam gi\u00e1c $ABC$ c\u00f3 $AB = 3, AC = 4, BC = 5.$ Khi \u0111\u00f3","\u0110\u00fang","Sai"],"arr_ques":["$AC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(B; 3)$ ","$AB$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(C; 4)$","$BC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(A; 3)$","$BC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(A; 2,4)$"],"explain":["\u0110\u00fang, ta c\u00f3 $AB^2+AC^2=BC^2$ $ \\Rightarrow \\Delta ABC $ vu\u00f4ng t\u1ea1i $A$ <br\/> Suy ra $AC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(B; 3)$ ","<br\/> \u0110\u00fang, v\u00ec $\\Delta ABC $ vu\u00f4ng t\u1ea1i $A$ $\\Rightarrow AB$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(C; 4)$ ","<br\/> Sai, v\u00ec h\u1ea1 $AH \\bot BC$ t\u1ea1i $H$ $\\Rightarrow AH.BC= AB.AC$ $ \\Rightarrow AH = 2,4$ <br\/> Suy ra $BC$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(A; 2,4)$","\u0110\u00fang"]}]}],"id_ques":1159},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"<span class='basic_left'>\u0110\u01b0\u1eddng th\u1eb3ng $xy$ c\u1eaft \u0111\u01b0\u1eddng tr\u00f2n $(0; 7)$ t\u1ea1i hai \u0111i\u1ec3m. Kho\u1ea3ng c\u00e1ch $d$ t\u1eeb t\u00e2m $O$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $xy$ b\u1eb1ng m\u1ed9t trong c\u00e1c gi\u00e1 tr\u1ecb sau:<\/span>","select":["A. $d= 7$","B. $0 < d < 7$","C. $0 \\le d< 7$ ","D. $d > 7$"],"explain":"V\u00ec \u0111\u01b0\u1eddng th\u1eb3ng $xy$ c\u1eaft \u0111\u01b0\u1eddng tr\u00f2n (0; 7) t\u1ea1i hai \u0111i\u1ec3m n\u00ean kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m $O$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $xy$ l\u00e0 $0 \\le d < 7$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span>","column":2}]}],"id_ques":1160},{"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":[[["2"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'> Cho \u0111\u01b0\u1eddng th\u1eb3ng $xy$ v\u00e0 m\u1ed9t \u0111i\u1ec3m $A$ c\u00e1ch $xy$ m\u1ed9t kho\u1ea3ng $6 cm.$ V\u1ebd \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $A,$ b\u00e1n k\u00ednh $10 cm.$ <br\/><b> C\u00e2u 1: <\/b> S\u1ed1 giao \u0111i\u1ec3m c\u1ee7a $xy$ v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n $(A)$ l\u00e0 _input_ <\/span>","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D11.jpg' \/><\/center><br\/>K\u1ebb $AH \\bot xy$ t\u1ea1i H $\\Rightarrow OH = 6 \\,(cm)$<br\/> Do $6 cm < 10 cm$ n\u00ean $xy$ c\u1eaft $(A)$ t\u1ea1i hai \u0111i\u1ec3m ph\u00e2n bi\u1ec7t<br\/>Suy ra s\u1ed1 giao \u0111i\u1ec3m c\u1ee7a $xy$ v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n $(A )$ l\u00e0 $2$<br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $2.$<\/span>"}]}],"id_ques":1161},{"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":[[["16"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng th\u1eb3ng $xy$ v\u00e0 m\u1ed9t \u0111i\u1ec3m $A$ c\u00e1ch $xy$ m\u1ed9t kho\u1ea3ng $6 cm.$ V\u1ebd \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $A,$ b\u00e1n k\u00ednh $10 cm.$ <br\/><b> C\u00e2u 2: <\/b> G\u1ecdi $B$ v\u00e0 $C$ l\u00e0 c\u00e1c giao \u0111i\u1ec3m c\u1ee7a \u0111\u01b0\u1eddng th\u1eb3ng $xy$ v\u00e0 $(A).$ <br\/> \u0110\u1ed9 d\u00e0i $BC$ l\u00e0_input_ $(cm)$<\/span>","explain":"<span class='basic_left'><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D12.jpg' \/><\/center><br\/> V\u00ec $AH \\bot xy$ n\u00ean $AH \\bot BC$ <br\/> $\\Rightarrow BH= HC =\\dfrac{BC}{2}$ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y cung) <br\/>X\u00e9t $\\Delta AHC$ vu\u00f4ng t\u1ea1i $ H$ <br\/> $AH^2+HC^2=AC^2\\\\ \\Rightarrow HC^2=10^2-6^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $ \\Rightarrow HC^2= 64$ <br\/> $\\Rightarrow HC =8\\,(cm) $$\\Rightarrow BC =2HC=16\\,(cm)$ <br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $16.$ <\/span><\/span>"}]}],"id_ques":1162},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"<span class='basic_left'>Ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n l\u00e0: <\/span>","select":[" <span class='basic_left'>A . M\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng \u0111i qua \u0111\u01b0\u1eddng tr\u00f2n v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi b\u00e1n k\u00ednh c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n \u0111\u00f3 <\/span>","<span class='basic_left'>B. M\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng \u0111i qua m\u1ed9t \u0111i\u1ec3m c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi b\u00e1n k\u00ednh \u0111i qua \u0111i\u1ec3m \u0111\u00f3<\/span>","<span class='basic_left'>C. M\u1ed9t tia \u0111i qua m\u1ed9t \u0111i\u1ec3m c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi b\u00e1n k\u00ednh \u0111i qua \u0111i\u1ec3m \u0111\u00f3<\/span> ","<span class='basic_left'>D. M\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng \u0111i qua m\u1ed9t \u0111i\u1ec3m c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi b\u00e1n k\u00ednh c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i \u0111i\u1ec3m \u0111\u00f3<\/span>"],"explain":"Ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n l\u00e0 m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng \u0111i qua m\u1ed9t \u0111i\u1ec3m c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi b\u00e1n k\u00ednh c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i \u0111i\u1ec3m \u0111\u00f3<br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 D<\/span>","column":1}]}],"id_ques":1163},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n $(O; R)$. $M$ l\u00e0 m\u1ed9t \u0111i\u1ec3m sao cho $OM = 3R.$ V\u1ebd ti\u1ebfp tuy\u1ebfn $MN$ v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n $(O)$ ($N$ l\u00e0 ti\u1ebfp \u0111i\u1ec3m). T\u00ednh \u0111\u1ed9 d\u00e0i $MN$ theo $R$<\/span>","select":["A. $2R$","B. $2\\sqrt{2}R$","C. $\\sqrt{10}R$ ","D. $\\sqrt{3}R$"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D9.jpg' \/><\/center><br\/> $MN$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ <br\/> $\\Rightarrow MN \\bot ON$ (theo t\u00ednh ch\u1ea5t ti\u1ebfp tuy\u1ebfn) <br\/> X\u00e9t $\\Delta OMN$ vu\u00f4ng t\u1ea1i $N$ <br\/> $ON^2+MN^2=OM^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $ \\Rightarrow MN^2=9R^2 - R^2 \\\\ \\Rightarrow MN^2=8R^2$ <br\/> $\\Rightarrow MN =2\\sqrt{2}R$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 B.<\/span>","column":2}]}],"id_ques":1164},{"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":[[3]],"list":[{"point":5,"ques":"<span class='basic_left'> Cho \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u00f3 b\u00e1n k\u00ednh $OA$ c\u00f3 \u0111\u1ed9 d\u00e0i l\u00e0 $6cm$, d\u00e2y $BC$ vu\u00f4ng g\u00f3c v\u1edbi $OA$ t\u1ea1i trung \u0111i\u1ec3m $N$ c\u1ee7a $OA.$ <br\/><b> C\u00e2u 1: <\/b> T\u1ee9 gi\u00e1c $OCAB$ 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/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D7.jpg' \/><\/center><br\/> $OA \\bot BC $ t\u1ea1i $N$ <br\/> $ \\Rightarrow BN = NC $ (quan h\u1ec7 vu\u00f4ng g\u00f3c gi\u1eefa \u0111\u01b0\u1eddng k\u00ednh v\u00e0 d\u00e2y cung) <br\/> X\u00e9t t\u1ee9 gi\u00e1c $OCAB$ c\u00f3: <br\/> $AN = NO$ (gi\u1ea3 thi\u1ebft) <br\/> $BN = NC$ (ch\u1ee9ng minh tr\u00ean) <br\/> $\\Rightarrow$ T\u1ee9 gi\u00e1c $OCAB$ l\u00e0 h\u00ecnh b\u00ecnh h\u00e0nh (d\u1ea5u hi\u1ec7u nh\u1eadn bi\u1ebft). <br\/>M\u00e0 $OA\\bot BC$ n\u00ean $OCAB$ l\u00e0 h\u00ecnh thoi (d\u1ea5u hi\u1ec7u nh\u1eadn bi\u1ebft). <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 C.<\/span><\/span>","column":2}]}],"id_ques":1165},{"time":24,"part":[{"title":"Ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"select":["A. $6\\sqrt{3}$","B. $2\\sqrt{3}$","C. $\\sqrt{3}$"],"ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n $(O)$ c\u00f3 b\u00e1n k\u00ednh $OA$ c\u00f3 \u0111\u1ed9 d\u00e0i l\u00e0 $6 cm,$ d\u00e2y $BC$ vu\u00f4ng g\u00f3c v\u1edbi $OA$ t\u1ea1i trung \u0111i\u1ec3m $N$ c\u1ee7a $OA.$ <br\/><b> C\u00e2u 2: <\/b> K\u1ebb ti\u1ebfp tuy\u1ebfn v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n t\u1ea1i $B,$ c\u1eaft \u0111\u01b0\u1eddng th\u1eb3ng $OA$ t\u1ea1i $F.$ <br\/> \u0110\u1ed9 d\u00e0i $BF$ l\u00e0 ?$(cm)$<\/span>","hint":"\u00c1p d\u1ee5ng h\u1ec7 th\u1ee9c c\u1ea1nh v\u00e0 g\u00f3c v\u00e0o tam gi\u00e1c $BOF$ \u0111\u1ec3 t\u00ednh c\u1ea1nh $BF$","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn<\/span><br\/><b> B\u01b0\u1edbc 1: <\/b> Ch\u1ee9ng minh $\\widehat{AOB}= 60^o$ <br\/><b> B\u01b0\u1edbc 2: <\/b> \u00c1p d\u1ee5ng h\u1ec7 th\u1ee9c c\u1ea1nh v\u00e0 g\u00f3c v\u00e0o tam gi\u00e1c $BOF$ \u0111\u1ec3 t\u00ednh c\u1ea1nh $BF$ <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i<\/span><br\/><center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D8.jpg' \/><\/center><br\/> Ta c\u00f3 $OCAB$ l\u00e0 h\u00ecnh thoi (theo c\u00e2u 1) <br\/> $\\Rightarrow AB = OB = OA = 6 cm$ <br\/> $\\Rightarrow\\Delta OAB$ \u0111\u1ec1u (\u0111\u1ecbnh ngh\u0129a) <br\/> $\\Rightarrow \\widehat{AOB }=60^o$ (t\u00ednh ch\u1ea5t) <br\/> L\u1ea1i c\u00f3 $\\widehat{OBF} = 90^o$ (t\u00ednh ch\u1ea5t ti\u1ebfp tuy\u1ebfn) <br\/> X\u00e9t $\\Delta OBF$ vu\u00f4ng t\u1ea1i $ B$ <br\/> \u00c1p d\u1ee5ng h\u1ec7 th\u1ee9c c\u1ea1nh v\u00e0 g\u00f3c trong tam gi\u00e1c vu\u00f4ng $OBF$ ta c\u00f3: <br\/> $BF = OB. tg \\widehat{BOF}$ $= OB. tg 60^o$ $=6\\sqrt{3}\\, (cm)$<\/span>"}]}],"id_ques":1166},{"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":"<span class='basic_left'>N\u1ebfu m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng v\u00e0 \u0111\u01b0\u1eddng tr\u00f2n ch\u1ec9 c\u00f3 . . . th\u00ec \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3 l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n<\/span>","select":["A. M\u1ed9t \u0111i\u1ec3m chung","B. Hai \u0111i\u1ec3m chung","C. Ba \u0111i\u1ec3m chung","D. \u0110\u00e1p \u00e1n kh\u00e1c"],"explain":"<span class='basic_left'>N\u1ebfu m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng v\u00e0 m\u1ed9t \u0111\u01b0\u1eddng tr\u00f2n ch\u1ec9 c\u00f3 <b> m\u1ed9t \u0111i\u1ec3m chung <\/b> th\u00ec \u0111\u01b0\u1eddng th\u1eb3ng \u0111\u00f3 l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A<\/span><\/span>","column":2}]}],"id_ques":1167},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<span class='basic_left'>\u0110\u01b0\u1eddng th\u1eb3ng $xy$ c\u1eaft \u0111\u01b0\u1eddng tr\u00f2n $(0; 6)$ t\u1ea1i m\u1ed9t \u0111i\u1ec3m. Kho\u1ea3ng c\u00e1ch $d$ t\u1eeb t\u00e2m $O$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $xy$ b\u1eb1ng m\u1ed9t trong c\u00e1c gi\u00e1 tr\u1ecb sau:<\/span>","select":["A. $d= 6$","B. $0 \\le d < 6$","C. $0 < d < 6$ ","D. $d > 6$"],"explain":"V\u00ec \u0111\u01b0\u1eddng th\u1eb3ng $xy$ c\u1eaft \u0111\u01b0\u1eddng tr\u00f2n $(0; 6)$ t\u1ea1i m\u1ed9t \u0111i\u1ec3m n\u00ean kho\u1ea3ng c\u00e1ch t\u1eeb t\u00e2m $O$ \u0111\u1ebfn \u0111\u01b0\u1eddng th\u1eb3ng $xy$ b\u1eb1ng b\u00e1n k\u00ednh \u0111\u01b0\u1eddng tr\u00f2n $(d= 6)$ <br\/><span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A<\/span>","column":2}]}],"id_ques":1168},{"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":[[["24"]]],"list":[{"point":5,"width":60,"content":"","type_input":"","type_check":"","ques":"<span class='basic_left'>Cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $O$ b\u00e1n k\u00ednh $10 cm$ v\u00e0 m\u1ed9t \u0111i\u1ec3m $A$ c\u00e1ch $O$ l\u00e0 $26 cm.$ K\u1ebb ti\u1ebfp tuy\u1ebfn $AB$ v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n ($B$ l\u00e0 ti\u1ebfp \u0111i\u1ec3m). \u0110\u1ed9 d\u00e0i c\u1ea1nh $AB$ l\u00e0_input_ $(cm)$ <\/span>","hint":"\u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00ed Pitago","explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D5.jpg' \/><\/center><br\/><span class='basic_left'> $AB$ l\u00e0 ti\u1ebfp tuy\u1ebfn c\u1ee7a \u0111\u01b0\u1eddng tr\u00f2n $(O)$ <br\/> $\\Rightarrow AB \\bot OB$ (theo t\u00ednh ch\u1ea5t ti\u1ebfp tuy\u1ebfn) <br\/> X\u00e9t $\\Delta OAB$ vu\u00f4ng t\u1ea1i $B$ c\u00f3: <br\/> $AO^2=AB^2+OB^2$ (\u0111\u1ecbnh l\u00ed Pitago) <br\/> $\\Rightarrow AB=\\sqrt{26^2-10^2}\\\\ \\Rightarrow AB= 24 \\,(cm)$<br\/><span class='basic_pink'>V\u1eady k\u1ebft qu\u1ea3 c\u1ea7n \u0111i\u1ec1n l\u00e0 $24.$<\/span>"}]}],"id_ques":1169},{"time":24,"part":[{"title":"H\u00e3y ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"<span class='basic_left'>Trong h\u1ec7 tr\u1ee5c t\u1ecda \u0111\u1ed9 cho \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $I$ c\u00f3 t\u1ecda \u0111\u1ed9 $(-1; -1)$ v\u00e0 b\u00e1n k\u00ednh \u0111\u01b0\u1eddng tr\u00f2n b\u1eb1ng $5.$ H\u00e3y x\u00e1c \u0111\u1ecbnh v\u1ecb tr\u00ed t\u01b0\u01a1ng \u0111\u1ed1i c\u1ee7a \u0111i\u1ec3m $M (-5; 0)$ \u0111\u1ed1i v\u1edbi \u0111\u01b0\u1eddng tr\u00f2n <\/span>","select":["A. $M$ n\u1eb1m trong \u0111\u01b0\u1eddng tr\u00f2n","B. $M$ n\u1eb1m tr\u00ean \u0111\u01b0\u1eddng tr\u00f2n","C. $M$ n\u1eb1m ngo\u00e0i \u0111\u01b0\u1eddng tr\u00f2n"],"explain":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/toan/hinhhoc/bai8/lv1/img\/H923_D6.jpg' \/><\/center> <span class='basic_left'><br\/> L\u1ea5y \u0111i\u1ec3m $A$ sao cho $AM \\bot AI$ <br\/> Theo h\u00ecnh v\u1ebd ta c\u00f3 $IA = 4 ; AM = 1$ <br\/> X\u00e9t $\\Delta IMA$ vu\u00f4ng t\u1ea1i $A$ <br\/> \u00c1p d\u1ee5ng \u0111\u1ecbnh l\u00ed Pitago ta c\u00f3: <br\/>$\\begin{align}IM^2&=IA^2+AM^2\\\\ &=4^2+1^2\\\\ &=17\\\\ &\\Rightarrow IM =\\sqrt{17} < 5\\\\ \\end{align}$ <br\/> Suy ra \u0111i\u1ec3m $M$ n\u1eb1m b\u00ean trong \u0111\u01b0\u1eddng tr\u00f2n t\u00e2m $I$ b\u00e1n k\u00ednh $5 cm$ <br\/><span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n l\u00e0 A.<\/span>","column":1}]}],"id_ques":1170}],"lesson":{"save":0,"level":1}}