Horea Raducan wrote:
> If one of the points is on the enclosing circle, is that a valid solution ?
>
>   
I wouldn't care about such details :
the points are defined by floating point coordinates : I'd say that 
defining a circle with a center and a radius in floating point which 
passes exactly through such points is most often impossible.
There are obvious exceptions like circles with zero radius and some 
values where there's no approximation in the computations but these 
cases aren't likely to matter here.

Lionel