Question

如图所示，已知AE垂直AB，AF垂直AC，AE=AB，AF=AC，求证。EC垂直BF

Answer 1

 

Answer 2

设BF角CE于O
∵△AEC ≌△ABF (已证)
∴∠AFB = ∠ACE
而AF⊥AC，AF=AC
∴△ACF是直角等腰三角形，∠AFC = ∠ACF = 45°
又∵在△CFO中，∠OFC = 45° -∠AFB，∠OCF = 45° +∠AFB
∴∠OFC 与∠OCF互余， ∠COF = 90°
∴EC⊥BF

追答

采纳一下吧

Answer 3

证全等