1. EXAMPLE 1
Classifying Solids
Classify the solid. Tell whether it is a polyhedron.
The solid has two congruent circular bases that lie in parallel planes, so it is a cylinder. It is not a polyhedron, because circles are not polygons.

2. Counting Faces, Edges, and Vertices
EXAMPLE 2
Counting Faces, Edges, and Vertices
Classify the solid. Then count the number of faces, edges, and vertices.
Remember to include the base when counting faces.
SOLUTION
The solid is a pentagonal pyramid.

3. EXAMPLE 3
Sketching a Solid
Show two ways to represent a triangular prism.
METHOD 1
Sketch the solid.
STEP 1
STEP 2
STEP 3
Sketch two
congruent bases
Connect the
vertices.
Make any hidden
lines dashed

4. EXAMPLE 3
Sketching a Solid
METHOD 2
Sketch the top, front, and side views of the solid.

5. GUIDED PRACTICE
for Examples 1, 2 and 3
Classify the solid. Then tell whether it is a polyhedron. 1.
All the faces of the solid are triangles. It
is a polyhedron and it is a triangular pyramid.
ANSWER 2.
It is a solid with one circular base. It is a cone and not a polyhedron.
ANSWER

6. GUIDED PRACTICE
for Examples 1, 2 and 3
Classify the solid. Then tell whether it is a polyhedron. 3.
It is an octagonal prism. It has octagonal and rectangular faces. It is polyhedron.
ANSWER

7. GUIDED PRACTICE
for Examples 1, 2 and 3
Show two ways to represent a rectangular pyramid. Then count the number of faces, edges, and vertices. 4.
5 faces, 8 edges, 5 vertices;
ANSWER