A sphere is a solid, all points of which are equidistant from a fixed point, the center, as shown in Figure 16.

The volume of a sphere is calculated using the following formula:

(3-15)

The surface area of a sphere is calculated using the following formula:

(3-16)

The surface area of a sphere is expressed in square units, and the volume of a sphere is expressed in cubic units.

Figure 16 Sphere

Example:

Calculate the volume and surface area of a sphere with r = 4". Be sure to include units in your answer.

Solution: