Some Sources for Cavalieri's Principle

Cavalieri for area and volume

This resource from EDC has good explanations and also problems. From this page, you should type

Cavalieri

in the search box

http://www2.edc.org/mathproblems/search.asp

These state and discuss Cavalieri for volume

The site from Math Forum has great graphics and illustrates the pyramids that we built

http://mathforum.org/mam/00/master/essays/B3D/2/volume.html

Other sites with volume

http://www.math.washington.edu/~king/coursedir/m445w02/class/conevol.html

http://mathworld.wolfram.com/CavalierisPrinciple.html