Cavalieri's Principle applies in many contexts, but this is the most fundamental.[br][br]This sketch was the idea of Jill Knaus (@JillKnaus) and goes with the start of a lesson plan for the Principle (Common Core HSG-GMD.A.2): [url]http://bit.ly/1hiHIUI[/url] [br][br]The sketch asks:[br]What do you notice?[br]What can you change? [br]Compare & contrast the triangles and their measures.[br]What do you wonder about?

More GeoGebra at [url]mathhombre.blogspot.com[/url].