The measure of the **exterior angle** $c$ is always the sum of the measures of $a$ and $b:$

To see how we know this and learn a couple of other useful facts, keep reading. Or, you can skip ahead to the challenge if you feel ready.

The measure of the **exterior angle** $c$ is always the sum of the measures of $a$ and $b:$

To see how we know this and learn a couple of other useful facts, keep reading. Or, you can skip ahead to the challenge if you feel ready.

Subscribe to Premium to get access to the full archives.

Subscribe now