Definition of Terms, Continued
Solids
(Continued)
Pyramids have polygons for a base and triangular lateral faces that intersect
at the vertex or top of the pyramid.
A centerline from the vertex to the
center of the base is known as the axis and its height is called the altitude.
If
the axis is perpendicular to the base, the pyramid is a right pyramid. All
other pyramids are oblique pyramids. A pyramid that has been cut off near
the vertex oblique to the base is said to be truncated; if the pyramid is cut off
parallel to the base, the cut plane is known as a frustum.
Figure 2-13 illustrates pyramid terminology.
Figure 2-13.—Pyramids.
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