This applet update of the original applet [url]434 Exterior Angles of Polygons[/url] with negative exterior angles so that the exterior angle sum is still 360° when the polygon becomes concave. It is suggested that teacher only uses this applet AFTER he/she has a thorough discussion with their students about the notion of negative angles USING THE ORIGINAL APPLET.
Anthony Or. GeoGebra Institute of Hong Kong.
