Download 11 – 3 Surface Area of Pyramids and Cones

11 – 3 Surface Area of Pyramids and Cones
Pyramids…what is a pyramid?
A pyramid is a solid figure that has one base. The
one base is a polygon shape and the other faces are
triangles. These triangles or lateral faces meet at a
common point called the vertex.
Just like a prism, you name the pyramid by the shape
of its base.
This should also be familiar…the altitude and the
height (h).
The altitude is the perpendicular segment that
extends from the vertex to the base. The length of
the altitude will be the height (h) of the pyramid.
Something different with pyramids, is the slant
height. The slant height (l) is the length of the
height of a lateral face (one of the triangles) of the
pyramid.
The lateral area and surface area
Something to keep in mind, pyramids have only one base.
Formula for Lateral area:
Lateral area = ½ (perimeter)(slant height)
Or
L.A. = ½ pl
And to find the Surface Area you just have to simply
add the area of the base (B).
Formula for Surface Area:
Surface Area = Lateral area + Area of the Base
Or
S.A. = L.A. + B
Homework: pg 740 – 741 # 7, 8, 10 – 12, 16 - 18