If two angles of a triangle are congruent, then the sides opposite these angles are also congruent

Given

Triangle ABC

Prove

AB = AC

Proof

Drawing See figure 2

Figure 2

1: - Given

2: AO = AO - Common

3: - From drawing See figure 2

4: - From 1,2,3 - If two angles and a nonincluded side of one triangle are congruent to two angles and a nonincluded side of a second triangle, then the triangles are congruent (AAS)

AB = AB - From 4