The volume of a cylinder is 60 cubic centimeters. The radius of the cylinder is 2. What is the number of cubic centimeters in the volume of the sphere that circumscribes the cylinder?
We can find the height of the cylinder as follows
60 = pi * 2^2 * height
15 / pi = height
Now.....the radius of the sphere can be found by the Pythagorean Theorem
We have a right triangle with one leg = the radius of the cylinder = 2 and the other = (1/2) the height of the cylinder = 7.5 / pi
The radius of the sphere is the hypotenuse of this triangle = sqrt [ 2^2 + (7.5/pi)^2 ] =
sqrt [ 4 + 56.25/pi^2 ] = [ 4 + 56.25 / pi^2]^(1/2)
The volume of this sphere = (4/3) pi * [ 4 + 56.25/pi^2] ^(3/2) ≈ 126.5 cm^3