External
Links
GeoGebra: an integrated
dynamic geometry and algebra sketchpad
NonEuclid:
A
Java-based hyperbolic geometry sketchpad
Spherical
Easel: A Java-based or downloadable spherical geometry sketchpad
Curved
Spaces: Interactive 3D program that allows you to explore different
flat, spherical, and hyperbolic spaces.
FirstClassHelp:
Online tutoring and community to address mathematics questions.
Euclid's
Elements: An online text of Euclid's Elements with useful
commentary.