EDGE Math 8

Theorem

If two angles are supplementary and congruent, then each is a right angle.

Given:	$∠ A B C$ and $∠ D E F$ are supplementary.
	$∠ A B C ≅ ∠ D E F$
Prove:	$∠ A B C$ and $∠ D E F$ are right angles.

Proof