Try this ACT math practice question on the internal angles of an octagon.

In a regular octagon, all $8$ interior angles are congruent. What is the measure of each interior angle of a regular octagon?

- $\quad 22.5^{\circ}$
- $\quad 45^{\circ}$
- $\quad 120^{\circ}$
- $\quad 135^{\circ}$
- $\quad 150^{\circ}$

**Video explanation**