- http://en.wikipedia.org/wiki/Pythagorean_theorem
- http://www.cut-the-knot.org/pythagoras/
- http://en.wikipedia.org/wiki/Pythagoras
- http://www.gap-system.org/~history/Biographies/Pythagoras.html
Here are some links to sites with really useful games:
And a link I made in Excel: