Applet informally illustrates to the student that the sum of the measures of the interior angles of any quadrilateral is 360 degrees, and that the sum of the measures of the exterior angles of any quadrilateral is 360 degrees.
This applet is a revision of the one found at http://tube.geogebra.org/m/1878165.
It was revised in order to help students develop the formula for the sum of the measures of the interior angles of any n-gon = 180(n - 2).
