题目内容：

矩形ABCD的面积为36,在AB、AD上分别取点E、F,使得AE=3BE,DF=2AF,ED与CF的交点为O,计算ΔFOD的面积.
矩形ABCD的面积为36,在AB、AD上分别取点E、F,使得AE＝3BE,DF＝2AF,ED与CF的交点为O,计算ΔFOD的面积.

优质解答

延长DE,CB交于M
AED相似于BEM
=>
BM/AD=EB/AE=1/3
=>
MC/AD = 4/3
MOC相似于FOD
MC/FD=OC/FO=4/2=2
=>
SΔFOD = FO/FC * SΔFDC =1/3SΔFDC = 1/3 * 1/3 S-ABCD = 4