## Spheres

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 represents a sphere with radius 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 Summary of formulas concerning geometric solids.

Figure 2 Summary of formulas concerning geometric solids.