Why Exterior angle always equal to 360 degrees?

The exterior angle of a polygon is formed by extending one side of the polygon at a vertex. The sum of the angles around a point is always 360 degrees, which includes the exterior angle and the adjacent interior angle. Since the interior angle and the exterior angle at a vertex are supplementary (they add up to 180 degrees), the exterior angle itself can be thought of in the context of multiple vertices around a point, leading to the total sum of all exterior angles of a polygon being equal to 360 degrees, regardless of the number of sides.