Answer:
135°
Explanation:
You want the measure of one internal angle of a regular octagon.
Internal angles
Each internal angle is the supplement of the adjacent external angle.
The sum of external angles is 360°. For a regular polygon, all angles of the same type have the same measure. That means the external angles are ...
360°/8 = 45°
and the internal angles are ...
x = 180° -45° = 135°