âAE=2EBâåºè¯¥æ¯âAE=2ECâå§ï¼
解çè¦ç¹æ示ï¼
è¿Bä½BG//BC交ADç延é¿çº¿äºG
å 为Dæ¯BCçä¸ç¹
æ以å¯è¯BGï¼AC
å 为AEï¼2EC
æ以å¯å¾AEâ¶ACï¼2â¶3
æ以AEâ¶BGï¼2â¶3
æ以OEâ¶OBï¼AEâ¶BGï¼2â¶3
å 为BDï¼CD
æ以Sâ³ABDï¼Sâ³ACDï¼Sâ³ABC/2
å 为â³ACDçé¢ç§¯ä¸º6å¹³æ¹åç±³ï¼
æ以Sâ³ABCï¼12å¹³æ¹åç±³
èâ³BCEé¢ç§¯â¶â³ABEçé¢ç§¯ï¼CEâ¶AEï¼1â¶2
æ以å¯æ±å¾â³ABEçé¢ç§¯ï¼8å¹³æ¹åç±³
å 为OEâ¶OBï¼2â¶3
æ以Sâ³AEOâ¶Sâ³ABOï¼2â¶3
æ以Sâ³ABOï¼Sâ³ABE*3/5ï¼4.8å¹³æ¹åç±³
æ以é´å½±çé¢ç§¯ï¼Sâ³ABCï¼Sâ³ABO
ï¼12ï¼4.8
ï¼7.2ï¼å¹³æ¹åç±³ï¼
ä¾åèï¼æ±èå´äºè¶ ç¥ä½ å¦ä¹ è¿æ¥
åèèµæï¼http://hi.baidu.com/jswyc/blog/item/5c960f3e305d16e054e7239c.html