Find the size of each interior angle in a regular octagon

To do this you divide 360 by 8 which equals 45

The exterior angle is 45°

So to find the interior angle you do 180-45=135

So one interior angle is 135°

The formula for finding the measure of interior angles in a regular octagon is

(the number of sides the shape has - 2) * 180 / the number of sides

(8-2) * 180 / 8

6*180 / 8 = 1080/8 = 135

The size of each interior angle in a regular octagon is 135°