If one exterior angle of a regular polygon is 20 degrees, what is the polygon? *

How many degrees in a polygon? All polygons have the same!! Divide that by 20 and you will find the answer.

Be careful!! You are given the exterior angle and not the interior angle.

The more sides a regular polygon has, the smaller the exterior angle will be.

Using the exterior angle, find the interior angle. (Interior angle = 180 - exterior angle)

Then you either use a formula, or you draw a picture and divide the polygon into equal triangles. Get the angle bounded by the two equal sides and divide 360 by that angle to get the number of sides in the polygon, hence the name.