And if we know that all four angles are 90 degrees and we've proven in previous videos how to figure out the sum of the interior angles of any polygon and using that same method, you could say that the sum of the interior angles of a rectangle, or of any, of any quadril, of any quadrilateral, is actually a hund- is actually 360 degrees, and you see that in this special case as well, but maybe we'll prove it in a separate video.