NAME ______________________________________________ DATE
11-1 Three-Dimensional Figures
____________ PERIOD _____
(Pages 556–561)
A flat surface that contains at least three noncollinear points and extends
infinitely in all directions is called a plane. Planes can intersect in a line,
at a point, or not at all. When multiple planes intersect they form threedimensional figures. These figures have flat polygonal sides and are called
polyhedrons. When looking at a polyhedron it is made of edges, where
two planes intersect in a line, vertices (singular is vertex), where three
or more planes intersect at a point, and faces, flat sides. There are many
types of polyhedrons, two of which are prisms and pyramids. A prism is a
polyhedron that has two identical sides that are parallel called bases. The
two bases are connected by rectangles. A pyramid has one base and has a
series of triangles that extend from the base to a point. To classify a prism
or a pyramid you must identify its base. For example, a pyramid with a
rectangular base is called a rectangular pyramid and a prism with a
triangular base is called a triangular prism.
Skew lines are lines that that do not intersect and are not parallel. In
fact, they do not even lie in the same plane. A diagonal line inside of a
polyhedron and an edge on the opposite side of the polyhedron would be
an example of skew lines.
Examples
Identify the three-dimensional shapes.
a.
b.
Figure A has two rectangular bases
and rectangles connecting its two
bases, so it is a rectangular prism.
Figure B has one triangular base
and consists of three triangles that
meet at a point, so it is and example
of a triangular pyramid.
Practice
Name the polyhedron.
1.
2.
3.
Answers: 1. triangular prism 2. hexagonal prism 3. rectangular pyramid
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Glencoe Pre-Algebra