**Proposed exercise**

Calculate the surface and volume of a sphere, given its radius (surface = 4 * pi * radius squared; volume = 4/3 * pi * radius cubed).

Hint: for "float" numbers, you must use Convert.ToSingle(...)

**Output**

**Solution**

using System; public class Sphere { public static void Main() { float radius; float pi = 3.1415926535f; Console.Write("Radius? "); radius = Convert.ToSingle(Console.ReadLine()); Console.WriteLine( 4 * pi * (radius * radius) ); Console.WriteLine( 4/3 * pi * (radius * radius * radius)); } }