So ∠ AED = 90, ∠ AFD = 90 (vertical meaning).

∠AED=∠AFD (equivalent substitution)

Because AD is the angular bisector of △ABC (known)

So ∠DAE=∠DAF (definition of angular bisector)

In δ δ△ADE and δ△ADF,

{_∠DAE=∠DAF_，

{∠AED=∠AFD，

{_ ad = ad _ (male * * *)

So △ADE is equal to△ △ADF (A.A.S).