If you're willing to tolerate an intersection function which has the 
possibility of error, it seems like just using bounding squares instead 
of bounding circles would give better error bounds if you expect your 
circles to often be of very different sizes.

With regard to the actual question you asked, I can't think of a good 
way without square roots off of the top of my head, but if you're 
willing to tolerate a bit of approximation error then computing them 
needn't be slow:

http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Approximations_that_depend_on_IEEE_representation

Post a reply to this message