What is the measure of an interior angle of a regular octagon?
A regular octagon has eight equal sides and eight equal angles.
Answer: The measure of an interior angle of a regular octagon is 135º.
Let's understand more about an interior angle of a regular octagon.
In a regular octagon, the interior angle at each vertex is 135º and the central angle is 45º.
Its interior angles add up to 1080° and the exterior angles add up to 360°.
Each exterior angle of an octagon = 360° / 8 = 45°
As interior angle and exterior angles are supplementary, ∠i + ∠e = 180°
∠i = 180° - 45° = 135°