Playing with Pythagoras

Geogebra is an amazing (free) tool for creating interactive math applets. I downloaded it yesterday, spent a few hours going through some tutorials and managed to create this applet related to the Pythagorean Theorem. Which I was pretty excited about. I would have liked to include sliders to change the size of the angles but I couldn't figure out how to link the slider to the angle. Anyone know how?

Not only that but it's super easy to add this to a Moodle web page. Which I've done.