Date: Apr 1, 2011 3:04 PM
Author: Michael de Villiers
Subject: Re: Inclusive and exclusive definitions... again!

Free dynamic Sketchpad 4 and Sketchpad 5 sketches that illustrate a Hierarchical Quadrilateral Tree can be downloaded from Sketchpad Exchange at

It shows the hierarchical relationships between several quadrilaterals as well as some of their their properties. Apart from the familiar ones, it includes isosceles trapezoids, cyclic & circumscribed quadrilaterals.

Hope teachers find it useful.