Question 317532: How many sides does a regular polygon have if one exterior angle is 90 degrees? Answer by Edwin McCravy(20056) (Show Source): You can put this solution on YOUR website! The sum of the exterior angles of any polygon is 360°. Suppose the
polygon has n sides. Since it is regular, all n exterior angles have
the same measure, so , so
It's a 4-sided regular polygon, so it's a square!:
Edwin