Pythagoras Puzzle

Aim: To fit all the coloured pieces into the outline squares. (without any overlap!) How: Click and drag to move the pieces. Rotate using the blue dots. Hint: The green pieces go in one square and the blue piece in the other.
Done it? Congratulations! Now have a think about the areas in the puzzle. The triangles all have the same area, so do the two outline squares. What about the other squares? Which is greater? The area of the blue square or the areas of the green squares added together? Start hitting the next arrow to find out more.