To calculate the surface area of a sphere, you have to use the following formula:

Where "r" is the radius of the sphere.
We know that the diameter of the sphere is d = 60 inches and that the radius is half the diameter, then the radius can be determined as follows:

Once the radius is calculated, you can determine the surface area of the sphere:

The surface area of the sphere is 3600π in², expressed as a decimal value, the surface area is equal to 11309.73 in²