In Fig. 6.40, EEE is a point on side CBCBCB produced of an isosceles triangle ABCABCABC with AB=ACAB = ACAB=AC. If AD⊥BCAD \perp BCAD⊥BC and EF⊥ACEF \perp ACEF⊥AC, prove that △ABD∼△ECF\triangle ABD \sim \triangle ECF△ABD∼△ECF.