∫AB∨FC

∴∠B=∠FCE (two straight lines are parallel and have the same included angle)

∫AD∨FE

∴∠ ADB =∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠∠

BC = DE

∴BC+CD=DE+CD

That is BD=CE.

In Abd and FCE

Big ∠B=∠FCE

Closed BD=CE

No ∠ADB=∠E

∴△Abd?△FCE

∴AD=FE (two corresponding sides of congruent triangles are equal)

Well, because braces are not easy to type, I have to write them.