How do I find the radius of a sphere?

Answer by  sadasada (146)

The radius of a sphere refers to the distance between any point on the surface of the sphere and the center of the sphere. The radius can be computed from other known quantities such as Area, diameter, surface area, volume, or etc. ; or it can be measured directly by using a string to measure circumference and using Circumference=2*Pi*R (R=Radius).

Answer by  worker3170 (9)

You can find the radius of a sphere by solving the equation: A = 4*PI*(radius*radius) for radius, where A is the sphere surface area. First I divide both sides by 4 * Pi: radius*radius = A /(4*Pi) then we take square root of both sides (and take only the positive root because radius is magnitude): radius=Sqrt(A/4*Pi)=(1/(2*Pi))*Sqrt(A*Pi)