延长BE交AC的延长线于F∵∠BFC+∠DAC=90°,∠BFC+∠CBF=90°∴∠DAC=∠CBF在⊿BCF,⊿ACD中∠DAC=∠CBF,AC=BC,∠ACD=∠BCF=90°∴⊿BCF≌⊿ACD∴AD=BF在⊿AEF,⊿ABF中∵∠AEF=∠AEB=90°,AE=AE,∠EAF=∠EAB∴⊿AEF≌...