Page 884 - Algebra 1

Three-Dimensional Figures
Skills Bank Lesson 23
A polyhedron is a three-dimensional figure that is made up of polygons which are called faces. A polyhedron has flat faces and straight edges. The faces intersect at edges. A vertex is any point in which three or more edges intersect.
Face
Vertex Edge
SKILLS BANK
Some three dimensional figures are not polyhedra because they are not made up of polygons.
Example 1 Determining Whether a Three-Dimensional Shape Is a Polyhedron
Determine whether the three-dimensional shape is a polyhedron. If yes, tell how many faces, edges, and vertices the shape has.
a.
SOLUTION
This shape is not a polyhedron.
Skills Bank Practice
b.
SOLUTION
This shape is a polyhedron. There are 6 faces, 12 edges, and 8 vertices.
Determine whether the three-dimensional shape is a polyhedron. If yes, tell how many faces, edges, and vertices the shape has.
a. b.
Skills Bank 869