Anybody care to guess how ugly the 'trig' solution is? Also, BrowserUK, why did you decide to go the trig route? Are you (as guessed below) coming from a navigator-type background? Most of us, as you will see, attacked this using basic algebra. Not that there is anything wrong with that :)

I will say, though, I do tend to make problems too hard myself. for instance, the US S.A.T. (that easy test was long long long ago) isn't supposed to require Calculus -- only basic Trig, but I used a few Integrals in random places just because. It's whatever tools that are sharpest that get used, I guess. My trig is kind of rusty. When I try to write OpenGL every now and then, I end up with some very weird physics :)

--FlyingMoose