find the radius of circle circumcribed about traingle has 3 known sides
The radius of the circumscribed circle is given by a neat formula, simply:
R = abc/(4*area)
where
a,b,c are the lengths of the sides of the triangle, and the area can be found using Heron's formula, namely:
Area = √(s(s-a)(s-b)(s-c))
and s=(a+b+c)/2