It is an octagon so exterior = 360/8=45 interior =180-45=135
exterior =360/20=18 interior =180-18=162
The formula for interior angles in a regular polygon is (180(n-2))/n so I need to rearrange this so n is on the left: (180(n-2))/n=176 180(n-2)=176n 180n-360=176n 4n=360 n=90 So there are 90 sides.
