Question

isosceles triangle Theorem 1

Answer 1

If two sides in a triangle are congruent, then the angles opposite the congruent sides are congruent angles.

Given: AB = AC

To prove: angle B = angle C

We are going to use congruent triangles to prove this. In order to do so we need two triangles which we can prove to be congruent. To accomplish this, construct AD bisecting angle A.