Boy, this will be embarassing if it is trivial or an FAQ:

Given 4 points (non coplanar), how does one find the sphere, that is,
center and radius, exactly fitting those points?  I know how to do it
for a circle (from 3 points), but do not immediately see a 
straightforward way to do it in 3-D.  I have checked some
geometry books, Graphics Gems, and Farin, but am still at a loss?
Please have mercy on me and provide the solution?  

Thanks,
Ed

