Answer: The measure of the interior angle of a regular octagon is 135 degrees.
Step-by-step explanation: All sides are the same length (congruent) and all interior angles are the same size (congruent). To find the measure of the angles, we know that the sum of all the angles is 1080 degrees (from above)... And there are eight angles... So, the measure of the interior angle of a regular octagon is 135 degrees.
