Then there is ∠EHB=∠BCA, ∠ HED = ∠ F.

AB = AC

∴∠B=∠BCA，

∴∠EHB=∠B

∴EH=EB

And EB=CF

∴EH=CF

∠EDH=∠FDC again

∠HED=∠F

∴△EDH is equal to △ △FDC.

So ED=FD