This is a nice way of demonstrating Pythagoras' Theorem. Moving the two blue points on the triangle change its size and shape. Show the lengths and then check that Pythagoras' theorem is correct.[br]The sliders demonstrate that the two small squares equal the big one.

This might look complicated. First the square changes to a parallelogram and then to a rectangle. Try to figure out why the area of each shape stays the same.[br]Thanks to Zen Biker Maniac for this applet.