{"common":{"save":0,"post_id":"6432","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"6439","mon_id":"1158767","chapter_id":"1158829","post_id":"6432","question":"<p>Cho <span class=\"math-tex\">$\\triangle ABC$<\/span> v\u1edbi các c\u1ea1nh <span class=\"math-tex\">$AB=c,AC=b,BC=a$<\/span> . G\u1ecdi <span class=\"math-tex\">$R,r,S$<\/span> l\u1ea7n l\u01b0\u1ee3t là bán kính \u0111\u01b0\u1eddng tròn ngo\u1ea1i ti\u1ebfp, n\u1ed9i ti\u1ebfp và di\u1ec7n tích c\u1ee7a tam giác <span class=\"math-tex\">$ABC$<\/span> . Tìm kh\u1eb3ng \u0111\u1ecbnh sai?<\/p>","options":["A. <span class=\"math-tex\">$S=\\frac{abc}{4R}$<\/span> .","B. <span class=\"math-tex\">$R=\\frac{a}{\\sin A}$<\/span> .","C. <span class=\"math-tex\">$S=\\frac{1}{2}ab\\sin C$<\/span> .","D. <span class=\"math-tex\">$a^2+b^2-c^2=2ab\\cos C$<\/span> ."],"correct":"2","level":"3","hint":"<p>Theo \u0111\u1ecbnh lí sin trong tam giác ta có: <span class=\"math-tex\">$S=\\frac{abc}{4R}$<\/span><\/p>","answer":"<p><span style=\"color:#27ae60;\"><strong>\u0110áp án: B<\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"147","test":"0","date":"2023-03-09 12:41:03","option_type":"math","len":0},{"id":"6440","mon_id":"1158767","chapter_id":"1158829","post_id":"6432","question":"<p>Ch\u1ecdn kh\u1eb3ng \u0111\u1ecbnh \u0111úng trong các kh\u1eb3ng \u0111\u1ecbnh sau?<\/p>","options":["A. <span class=\"math-tex\">$S=\\frac{1}{2}bc\\sin A$<\/span>","B. <span class=\"math-tex\">$S=\\frac{1}{2}ac\\sin A$<\/span>","C. <span class=\"math-tex\">$S=\\frac{1}{2}bc\\sin C$<\/span>","D. <span class=\"math-tex\">$S=\\frac{1}{2}bc\\sin B$<\/span>"],"correct":"1","level":"3","hint":"<p>Công th\u1ee9c tính di\u1ec7n tích tam giác: <span class=\"math-tex\">$S=\\frac{1}{2}bc\\sin A=\\frac{1}{2}ab\\sin C=\\frac{1}{2}ac\\sin B$<\/span><\/p>","answer":"<p><span style=\"color:#27ae60;\"><strong>\u0110áp án: A<\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"147","test":"0","date":"2023-03-09 12:44:37","option_type":"math","len":0},{"id":"6441","mon_id":"1158767","chapter_id":"1158829","post_id":"6432","question":"<p>Cho tam giác <span class=\"math-tex\">$ABC$<\/span> có góc <span class=\"math-tex\">$\\angle BAC=60^o$<\/span> và c\u1ea1nh <span class=\"math-tex\">$BC=6$<\/span> . Tính bán kính c\u1ee7a \u0111\u01b0\u1eddng tròn ngo\u1ea1i ti\u1ebfp tam giác <span class=\"math-tex\">$ABC$<\/span> .<\/p>","options":["A. <span class=\"math-tex\">$R=4\\sqrt3$<\/span> .","B. <span class=\"math-tex\">$R=2\\sqrt3$<\/span> .","C. <span class=\"math-tex\">$R=2$<\/span> .","D. <span class=\"math-tex\">$R=4$<\/span> ."],"correct":"2","level":"3","hint":"<p> Áp d\u1ee5ng \u0111\u1ecbnh lí sin cho tam giác <span class=\"math-tex\">$ABC$<\/span> <\/p>","answer":"<p><span style=\"color:#27ae60;\"><strong>\u0110áp án: B<\/strong><\/span><\/p><p> Áp d\u1ee5ng \u0111\u1ecbnh lí sin cho tam giác <span class=\"math-tex\">$ABC$<\/span> ta có: <span class=\"math-tex\">$\\frac{BC}{\\sin A}=2R\\Rightarrow2R=\\frac{6}{\\sin60^o}=4\\sqrt3\\Rightarrow R=2\\sqrt3$<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"147","test":"0","date":"2023-03-09 12:49:45","option_type":"math","len":0}]}
