AB=CD,∠A=∠C
∴△ABE≌△CDF(ASA)
∴AE=CF
4、BE = CF
Then BE+EF+EF+CF
∴BF=CE
BF = CE,∠A=∠D,∠B=∠C
∴△ABF≌△DCE(AAS)
∴AB=DC