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:
![](https://s3.amazonaws.com/dev-hmhco-vmg-craftcms-public/_cliffsnotes/assets/18648.jpg)
Theorem 100: The volume of a sphere, V, with radius r is given by the following equation:
![](https://s3.amazonaws.com/dev-hmhco-vmg-craftcms-public/_cliffsnotes/assets/18649.jpg)
Example 1: Figure 1 represents a sphere with radius r. If r = 9 cm, find (a) S and (b) V.
![](http://cliffsnotescms-v1.stage.techspa.com/assets/18667.jpg)
Figure 1 Finding the surface area and volume of a sphere.
![](https://s3.amazonaws.com/dev-hmhco-vmg-craftcms-public/_cliffsnotes/assets/18650.jpg)
See Figure 2 Summary of formulas concerning geometric solids.
![](http://cliffsnotescms-v1.stage.techspa.com/assets/18668.jpg)
Figure 2 Summary of formulas concerning geometric solids.