Theorem 9.1.2

Theorem 9.1.2: If two angles of a triangle are congruent, then the sides opposite to them are also congruent.

Proof:

Given: In $\triangle ABC$ We have, $\angle B \cong \angle C$

To prove:

$\overline{AB}\cong\overline{AC}$

Construction: Draw a line $\overline{AD}$ the bisector of $\angle A$, meeting $\overline{BC}$ at point $D$.

Proof: