1. 12.2 Surface Areas of Pyramids
Objective
After studying this section, you will be able to find the surface areas of pyramids

2. Pyramids
A pyramid has only one base. Its lateral edges are not parallel but meet at a single point called the vertex. The base may be any polygon, but the lateral faces will always be triangles. We name pyramids by their base.

3. Regular Pyramids
A regular pyramid has a regular polygon as its base and also has congruent lateral edges. The lateral faces of a regular pyramid are congruent isosceles triangles.

4. Parts of Pyramids Slant height - the height of a lateral face.
altitude- the perpendicular segment from the vertex to the base. (The foot of the altitude is the center of the base.)
A regular pyramid’s slant height and altitude determine a right triangle.
The altitude and a lateral edge determine a right triangle.

5. Example 1 Given the regular pyramid shown Find
a. the lateral area (L.A.)
b. the total area (T.A.) 10 12

6. Example 2
The base of rectangular pyramid ABCDE is 10 by 18. The altitude is 12. The lateral edges are congruent.
A. Why is ABCDE not a regular pyramid?
B. Find the pyramid’s total surface area. A E D F B C