应该是∠ACB=90°
证明:
∵∠ACB=90°,CD⊥AB
∴AC²=AD*AB
∵∠ACB=90°,CF⊥AE
∴AC²=AE*AF
∴AD*AB=AE*AF
∴AD/AF=AE/AB
∵∠DAF =∠EAB
∴△DAF∽△EAB
∴∠AFD =∠B
应该是∠ACB=90°
证明:
∵∠ACB=90°,CD⊥AB
∴AC²=AD*AB
∵∠ACB=90°,CF⊥AE
∴AC²=AE*AF
∴AD*AB=AE*AF
∴AD/AF=AE/AB
∵∠DAF =∠EAB
∴△DAF∽△EAB
∴∠AFD =∠B