You can put this solution on YOUR website! The sum of the exterior angles in any convex polygon is 360, so you can divide 360 by the number of vertices (sides) to obtain the degree measure of each exterior angle (e.g. for a pentagon, exterior angle = 360/5 = 72). To find the interior angle, simply subtract this angle measure from 180.
Alternatively, you can use the formula 180(n-2)/n to find the interior angle.