Hi Aardvajk. I don't actually calculate the distance, since it is not needed. If you want the distance, you need to solve the Pythagorean theorem, which means calling square root. It's getting late here in Europe so I won't go into a lengthy explanation on SAT, but here are some links you might find useful:

http://www.geometrictools.com/Documentation/MethodOfSeparatingAxes.pdf