Download Geometry 12-5: Surface Areas of Pyramids A. Lateral Areas of

Geometry 12-5: Surface Areas of Pyramids
A. Lateral Areas of Regular Pyramids
1. All the faces, except the base, intersect at one point called the _____________.
2. The base is always a _______________.
3. The faces that intersect at the vertex are called the _______________________
and form triangles. The edges of the lateral faces that have the vertex as an
endpoint are called ____________________.
4. The _____________ is the segment from the vertex perpendicular to the base.
5. If the base of a pyramid is a regular polygon and the segment with endpoints
that are the center of the base and the vertex is perpendicular to the base, then the
pyramid is called a ________________________. They have specific
characteristics. The altitude is the segment with endpoints that are the center of
the base and the vertex. All of the lateral faces are congruent isosceles triangles.
The height of each lateral face is called the _____________________ l of the
pyramid.
6. If a regular pyramid has a lateral area of L square units, a slant height of l units,
and its base has a perimeter of P units, then L = ________________.
Example 1: The roof o f a birdhouse is a regular hexagonal pyramid. The base of
the pyramid has sides of 4 inches, and the slant height of the roof is 12 inches. If
the roof is made of copper, find the amount of copper used for the roof.
B. Surface Areas of Pyramids
1. The surface area of a pyramid is the sum of the lateral area and the area
of the base.
2. If a regular pyramid has a surface area of T square units, a slant height
of l units, and its base has a perimeter of P units and an area of B square
units, the T = ______________.
Example 2: Find the surface area of the square pyramid.
Example 3: Find the surface area of the regular pyramid.
Geometry 12-5 p. 663-665
8-18 even, 21-23, 29-39 odd, 42-44