如图,AC,BD,EF相交于O,且AO＝CO,BO＝DO,EO＝OF,求证△ABE≌△CDF

OA=OC,OD=OB,角AOB=角COD,所以△AOB≌△COD 则AB=CD
同理：OA=OC,OE=OF,角AOE=角COF,所以△AOE≌△COF 则AE=CF
OB=OD,OE=OF,角BOE=角DOF,所以△BOE≌△DOF 则BE=DF
因为 AB=CD AE=CF BE=DF
所以 △ABE≌△CDF