Given: Line BDEC, AB is congruent to AC, BD is congruent to CE

Prove: Triangle ABD is congruent to Triangle ACE

Triangle ABC is an isosceles triangle
If two sides of a triangle are equal, the angles opposite them are equal
Line BDEC, AB is congruent to AC, BD is congruent to CE
Given
SAS (Side-Angle-Side)
Angle B is congruent to Angle C
Triangle ABD is congruent to Triangle ACE
Definition