GEOMETRY IN ACTION (G.I.A.), from Key College Publishing, is a discovery-oriented book of topics for original sketch-writing on The Geometer's Sketchpad.
Students who create their own sketches really learn geometry!
If your computer has a Java browser, take a look at some of the sketches listed below, especially those marked with asterisks. Then visit Geometry in Action at Key College Publishing.
Circles ***
Deltoid1 ***
EulerEnvelope ***
Humanoid1 ***
InvertCircle ***
PonceletPorism ***
Rotate ***
SimpleHarmonicMotion ******
Triangle Centers (access to lists of classical and recent centers)
Encyclopedia of Triangle Centers (more than 1000 triangle centers)