AC = AE Given
AB = AD Given
Angle BAC = Angle EAD Vertical Angles are always equal.
Triangle ABC is congruent to Triangle ADE *** Whenever 2 sides and the INCLUDED Angle of 2 triangles are equal then the triangles are congruent.
This is "Side - Angle - Side Congruency"
https://en.wikipedia.org/wiki/Congruence_(geometry)#Congruence_of_triangles
