If you google center of gravity or center of mass, one result is in
Wikipedia. Go to the subtopic: Locating the center of mass of an arbitrary
2D physical shape. That should guide you along the way.
If you'd like to see an interestting demonstration of center of gravity,
check out this post by Paul Herber: Centre of gravity of several shapes,
http://visguy.com/vgforum/index.php?topic=429.msg1925#msg1925
HTH
Wapperdude
