解ï¼å¦å¾
âµSâ³AOD:Sâ³ABD=2:5
â´è®¾Sâ³AOD=2x,Sâ³ABD=5x(xï¼0),å
Sâ³AOB=Sâ³ABDï¼Sâ³AOD=3x
Sâ³CODï¼Sâ³ACDï¼Sâ³AOD=Sâ³ABDï¼Sâ³AOD=5x-2x=3x
â´Sâ³AOD/Sâ³AOB=Sâ³COD/Sâ³BOC=DO/OB
å³2x/3x=3x/Sâ³BOC
â´Sâ³BOC=4.5x
â´Sâ³AOD:Sâ³BOC=2x:4.5x=4â¶9