在Rt△AFC与Rt△AEB中
∠A = ∠A ∠AEB = ∠AFC
所以,Rt△AFC∽Rt△AEB
AF :AC = AE :AB
即 AF :AE = AC:AB 且∠A = ∠A
所以,△AFE∽△ACB
∠AEF = ∠ABC