A **sphere** is the set of all points in space that are equidistant from a fixed point (the *center*).That distance is the **radius of the sphere**. Because a sphere has no bases, its area is referred to as its **surface area**.

*Theorem 99:* The surface area, *S*, of a sphere with radius *r* is given by the following equation:

*Theorem 100:* The volume of a sphere, *V*, with radius *r* is given by the following equation:

**Example 1:** Figure 1 *r*. If *r* = 9 cm, find (a) *S* and (b) *V*.

**Figure 1 **Finding the surface area and volume of a sphere.

See Figure 2

**Figure 2 **Summary of formulas concerning geometric solids.