
 
returns the squared radius of $$s.  

 
returns the squared radius of the sphere passing through $$p, $$q, $$r
and $$s. Precondition: p, q, r and s are not coplanar.  

 
returns the squared radius of the sphere passing through $$p, $$q and $$r, and whose center is in the plane defined by these three points.  

 
returns the squared radius of the smallest circle passing through $$p, and $$q, i.e. one fourth of the squared distance between $$p and $$q. 