Question

the measure of an exterior angle of a regular n-gon is 72. Classify the polygon by number of sides. What is it??

Answer 1

Are you familiar with exterior angles of a polygon?

The sum of the measures of the exterior angles of a polygon, one per vertex, is 360.
It does not make a difference how many sides the polygon has. The sum is always 360.

Answer 2

Apply the same idea as above to your polygon.
In my example, I knew it had 8 sides, and I found the measure of each exterior angle.
In your case, you know how much each exterior angle measures, and you are looking for the number of sides.

Answer 3

ahhh, okay thank you a lot!

Answer 4

You're welcome.