{"common":{"save":0,"post_id":"1353","level":1,"total":20,"point":5,"point_extra":0},"segment":[{"id":"1891","post_id":"1353","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"H\u00e3y ch\u1ecdn m\u1ec7nh \u0111\u1ec1 \u0111\u00fang: Trung tuy\u1ebfn c\u1ee7a m\u1ed9t tam gi\u00e1c l\u00e0 m\u1ed9t \u0111o\u1ea1n th\u1eb3ng","select":["<span class='basic_left'> A. Chia di\u1ec7n t\u00edch tam gi\u00e1c th\u00e0nh hai ph\u1ea7n b\u1eb1ng nhau <\/span> ","<span class='basic_left'> B. Chia \u0111\u00f4i m\u1ed9t g\u00f3c c\u1ee7a tam gi\u00e1c <\/span> ","<span class='basic_left'>C. Vu\u00f4ng g\u00f3c v\u1edbi m\u1ed9t c\u1ea1nh v\u00e0 \u0111i qua trung \u0111i\u1ec3m c\u1ee7a c\u1ea1nh \u0111\u00f3 <\/span> ","<span class='basic_left'> D. Xu\u1ea5t ph\u00e1t t\u1eeb \u0111\u1ec9nh v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi c\u1ea1nh \u0111\u1ed1i di\u1ec7n <\/span> "],"hint":"","explain":"<span class='basic_left'> A - \u0110\u00fang v\u00ec: <br\/> <center><img src='img\/H7C3B20_D11.png' \/><\/center> <br\/> G\u1ecdi $AM$ l\u00e0 trung tuy\u1ebfn c\u1ee7a $\\triangle{ABC}$ <br\/> Ta c\u00f3: $S_{\\triangle{ABC}} = \\dfrac{1}{2} AH . BC$ (1) <br\/> $S_{\\triangle{ABM}} = \\dfrac{1}{2}AH . BM$ (2) <br\/> $S_{\\triangle{AMC}} = \\dfrac{1}{2}AH . MC$ (3) <br\/> M\u1eb7t kh\u00e1c $BM = MC = \\dfrac{1}{2}BC$ (v\u00ec $M$ l\u00e0 trung \u0111i\u1ec3m c\u1ee7a $BC$) (4) <br\/> T\u1eeb (1), (2), (3), (4) $\\Rightarrow$ $S_{\\triangle{ABM}} = S_{\\triangle{AMC}} = \\dfrac{1}{2}S_{\\triangle{ABC}}$ <br\/> B _ Sai v\u00ec \u0111\u01b0\u1eddng chia \u0111\u00f4i m\u1ed9t g\u00f3c c\u1ee7a tam gi\u00e1c l\u00e0 <b> \u0111\u01b0\u1eddng ph\u00e2n gi\u00e1c <\/b> <br\/> C - Sai v\u00ec \u0111\u01b0\u1eddng vu\u00f4ng g\u00f3c v\u1edbi m\u1ed9t c\u1ea1nh v\u00e0 \u0111i qua trung \u0111i\u1ec3m c\u1ee7a c\u1ea1nh \u0111\u00f3 l\u00e0 <b> \u0111\u01b0\u1eddng trung tr\u1ef1c <\/b> <br\/> D - Sai v\u00ec \u0111\u01b0\u1eddng xu\u1ea5t ph\u00e1t t\u1eeb \u0111\u1ec9nh v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi c\u1ea1nh \u0111\u1ed1i di\u1ec7n l\u00e0 <b> \u0111\u01b0\u1eddng cao <\/b> <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span> <br\/> <span class='basic_green'><i> Nh\u1eadn x\u00e9t: \u1ede b\u00e0i n\u00e0y ta \u0111\u00e3 s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh di\u1ec7n t\u00edch hai tam gi\u00e1c <br\/> +) N\u1ebfu hai tam gi\u00e1c c\u00f3 c\u00f9ng chi\u1ec1u cao, c\u1ea1nh \u0111\u00e1y c\u1ee7a tam gi\u00e1c n\u00e0y t\u1ec9 l\u1ec7 c\u1ea1nh \u0111\u00e1y c\u1ee7a tam gi\u00e1c kia theo t\u1ec9 s\u1ed1 k th\u00ec di\u1ec7n t\u00edch c\u1ee7a tam gi\u00e1c n\u00e0y c\u0169ng t\u1ec9 l\u1ec7 v\u1edbi di\u1ec7n t\u00edch c\u1ee7a tam gi\u00e1c kia theo t\u1ec9 s\u1ed1 k <br\/> +) N\u1ebfu hai tam gi\u00e1c c\u00f3 c\u00f9ng chung c\u1ea1nh \u0111\u00e1y, nh\u01b0ng chi\u1ec1u cao c\u1ee7a tam gi\u00e1c n\u00e0y t\u1ec9 l\u1ec7 v\u1edbi chi\u1ec1u cao c\u1ee7a tam gi\u00e1c kia theo t\u1ec9 s\u1ed1 k, th\u00ec di\u1ec7n t\u00edch c\u1ee7a tam gi\u00e1c n\u00e0y c\u0169ng t\u1ec9 l\u1ec7 v\u1edbi di\u1ec7n t\u00edch c\u1ee7a tam gi\u00e1c kia theo t\u1ec9 s\u1ed1 k <\/b> <\/span> ","column":1}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:23:05"},{"id":"1892","post_id":"1353","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":10,"ques":"N\u1ebfu $G$ l\u00e0 tr\u1ecdng t\u00e2m c\u1ee7a tam gi\u00e1c $PQR$ v\u00e0 $PX$ l\u00e0 m\u1ed9t trung tuy\u1ebfn c\u1ee7a tam gi\u00e1c th\u00ec t\u1ef7 s\u1ed1 $\\dfrac{PG}{GX}$ b\u1eb1ng:","select":["A. $1:1$ ","B. $3:1$ ","C. $2:1$","D. $3:2$"],"hint":"","explain":"<span class='basic_left'> <center><img src='img\/H7C3B20_D12.png' \/><\/center> <br\/> V\u00ec $G$ l\u00e0 tr\u1ecdng t\u00e2m c\u1ee7a tam gi\u00e1c $PQR$ n\u00ean theo t\u00ednh ch\u1ea5t tr\u1ecdng t\u00e2m ta c\u00f3: <br\/> $PG = \\dfrac{2}{3}PX$ <br\/> $\\Rightarrow$ $GX = \\dfrac{1}{3}PX$ <br\/> $\\Rightarrow$ $\\dfrac{PG}{GX} = \\dfrac{2}{3}PX : \\dfrac{1}{3}PX = 2$ <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: C <\/span> ","column":4}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:23:05"},{"id":"1893","post_id":"1353","mon_id":"0","chapter_id":"0","question":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","options":{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"Cho tam gi\u00e1c $ABC$. Tr\u00ean tia \u0111\u1ed1i c\u1ee7a tia $BA$ l\u1ea5y \u0111i\u1ec3m $D$ sao cho $BD = BA$. Tr\u00ean c\u1ea1nh $BC$ l\u1ea5y \u0111i\u1ec3m $G$ sao cho $BG = \\dfrac{1}{3}BC$. Khi \u0111\u00f3 $G$ l\u00e0 tr\u1ecdng t\u00e2m c\u1ee7a tam gi\u00e1c $ACD$. <b> \u0110\u00fang <\/b> hay <b> sai <\/b>? ","select":[" A. \u0110\u00daNG ","B. SAI "],"hint":"M\u1ed9t \u0111i\u1ec3m l\u00e0 tr\u1ecdng t\u00e2m c\u1ee7a tam gi\u00e1c khi v\u00e0 ch\u1ec9 khi n\u00f3 thu\u1ed9c \u0111\u01b0\u1eddng trung tuy\u1ebfn v\u00e0 \u0111\u1ed9 d\u00e0i t\u1eeb \u0111i\u1ec3m \u0111\u00f3 t\u1edbi \u0111\u1ec9nh b\u1eb1ng $\\dfrac{2}{3}$ \u0111\u1ed9 d\u00e0i \u0111\u01b0\u1eddng trung tuy\u1ebfn \u0111i qua \u0111\u1ec9nh \u1ea5y. ","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 $CB$ l\u00e0 \u0111\u01b0\u1eddng trung tuy\u1ebfn <br\/> <b> B\u01b0\u1edbc 2: <\/b> Ch\u1ee9ng minh $M \\in BC$ v\u00e0 $CG = \\dfrac{2}{3}BC$ <br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <center><img src='img\/H7C3B20_D22.png' \/><\/center> <br\/> Trong tam gi\u00e1c $ACD$ c\u00f3: <br\/> $AB = BD$ (gt) $\\Rightarrow$ $CB$ l\u00e0 \u0111\u01b0\u1eddng trung tuy\u1ebfn (1) <br\/> M\u1eb7t kh\u00e1c ta c\u00f3: $BG = \\dfrac{1}{3}BC$ (gt) $\\Rightarrow$ $CG = \\dfrac{2}{3}BC$ (2) <br\/> T\u1eeb (1) v\u00e0 (2) $\\Rightarrow$ $G$ l\u00e0 tr\u1ecdng t\u00e2m c\u1ee7a tam gi\u00e1c $ACD$ (t\u00ednh ch\u1ea5t tr\u1ecdng t\u00e2m) <br\/> V\u1eady kh\u1eb3ng \u0111\u1ecbnh tr\u00ean l\u00e0 <span class='basic_pink'> \u0110\u00daNG <\/span> ","column":2}]}]},"correct":"","level":"1","hint":"","answer":"","type":"json","extra_type":"","time":"0","user_id":"0","test":"0","date":"2019-09-30 09:23:05"}]}