∵AD⊥BC
∴∠BDF=∠ADC=90°
∵BD=AD DF=DC
∴△ACD≌△BDF
∴BF=AC ∠BFD=∠ACD
∵∠BFD=∠AFE
∴∠AFE=∠ACD
∵∠DAC=∠FAE
∴△ACD∽△AEF
∴∠AEF=∠ADC=90°
∴BE(BF⊥AC
∴BF=AC且BF⊥AC