How do I prove the sides opposite the congruent base angles of triangle are congruent

Question

anonymous · Answer

Quite easy....
Congruence between two triangles means six items, all three sides and all three angles, are congruent. Thus the statement ABC  DEF has a very precise meaning. It succinctly summarizes the six statements (assume lines atop these segments): ABDE, BCEF, ACDF, AD, BE, and CF. It is very important to maintain the vertices in the proper order. Not doing so is a common mistake....

anonymous · Answer

There's one theorem called base angle theorem for this....
 states that if two sides in a triangle are congruent, then the angles opposite to these sides are also congruent.