Proof of Sum of the Exterior Angles of a Polygon

After proving that the sum of the interior angles of a polygon is 180(n-2), where n is the number of sides, let us now prove that the sum of the exterior angles is 360 degrees. The exterior angle of a polygon is the angle formed after extending one side of a polygon. It is the supplementary of the adjacent interior angle.

The proof uses the polygon angle sum theorem.