Pythagoras' Theorem 2
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. 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. Thanks to Zen Biker Maniac for this applet.