Known: △ ABC ≌ △ EDC. Verification: be = ad

Known: △ ABC ≌ △ EDC. Verification: be = ad

It is proved that: ∵ ABC ≌ EDC, ≌ AC = CE, BC = CD, ≌ ACB = ≌ ECD, ≌ ACB + ≌ ace = ≌ ECD + ≌ ace, that is, ≌ BCE = ≌ ACD, BC = CD ≌ BCE = ≌ dcace = AC, ≌ BCE ≌ DCA (SAS), ≌ be = ad