Ckeckout the following:
www dot geocities dot com slash bractals slash quad5 dot jpg
It shows five configurations of quadrilaterals.
The solid black lines are the sides of the
quadrilateral, the thin black lines are
construction lines to find the centroids, and
the red lines are the ones that pass through
the same point.
1) Parallelogram where the four lines merge
into two lines
2) Convex
3) Reflex
4) Concave
5) Concave where one of the vertices of the
quadrilateral coincides with its
corresponding centroid

Posted by Bractals
on 20080309 16:00:00 