A **right circular cone** is similar to a regular pyramid except that its base is a circle. The vocabulary and equations pertaining to the right circular cone are similar to those for the regular pyramid. Refer to Figure 1 for the vocabulary regarding right circular cones.

**Figure 1 ***A right circular cone.*

*Theorem 96:* The lateral area, *LA*, of a right circular cone with base circumference *C* and slant height *l* is given by the following equation.

*Theorem 97:* The total area, *TA*, of a right circular cone with lateral area *LA* and base area *B* is given by the following equation.

*Theorem 98:* The volume, *V*, of a right circular cone with base area *B* and altitude *h* is given by the following equation.

**Example 1:** Figure 2 is a right circular cone; find (a) *LA* (b) *TA* and (c) *V*.

**Figure 2 **Finding the lateral area, total area, and volume of a right circular cone.

(a)

The slant height, radius, and altitude of a right circular cone form a right triangle, as shown in Figure 3.

**Figure 3 **The right triangle formed by the slant height, radius, and altitude of a right circular cone.

- (b)

- (c)