Circles

Trying to get my worms to turn on a circular path has been quite frustrating. I want them to traverse a circle of given radius until pointing at the destination, at which time they just move straight there. I ended up creating an equation with variables for an angle, the radius, and the destination x and y, then solved for the angle in Mathematica. This seems to work, but produces odd singularities around x=0, and is generally being a pain in the ass. Now it's about time for sleep... it's hard programming all day at work then doing this all evening.