Download Geometry 12-6: Surface Area of Cones A. Lateral Area of Cones 1

Geometry 12-6: Surface Area of Cones
A. Lateral Area of Cones
1. Cones have a base that is a ______________ and a vertex.
2. The _________ is the segment whose endpoints are the vertex and the center of
the circle.
3. The segment that has the vertex as one endpoint and is perpendicular to the
base is called the ________________ of the cone.
4. A cone with an axis that is also an altitude is called a ____________________.
Otherwise, it is an _________________________________.
5. If a right circular cone has a lateral area of L square units, a slant height of l
units, and the radius of the base is r units, then L = ____________.
Example 1: A conical lampshade has an altitude of 6 inches and a diameter of 12
inches. What is the lateral area of the lampshade?
B. Surface Areas of Cones
1. To find the surface area of a cone, add the area of the base to the lateral
area.
2. If a right circular cone has a surface area of T square units, a slant
height of l units, and the radius of the base is r units, then
T=_________________.
Example 2: Find the surface area of the cone.
Geometry 12-6 p. 668-670
8-20 even, 24, 34-35, 37-55 odd