Question

向△abc外作正方形abef和acgh,求证cf=bh

Answer 1

AB=AC么? 如果等于的话 就是 ：证明：∵正方形ABEF和正方形ACGH,∴AC=AH,AB=AF,∠BAF=∠CAH=90°.∵∠CAF=∠BAC+90°,∠BAH=∠BAC+90°∴∠CAF=∠BAH.∵AB=AC,且AB=AF,AC=AH,∴AF=AH.∴△CAF≡BAH（SAS——∴CF=BH