EXAMPLE 1

1. Classify the solid. Tell whether it is a polyhedron. EXAMPLE 1 Classifying Solids 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. Classify the solid. Then count the number of faces, edges, and vertices. The solid is a pentagonal pyramid. Remember to include the base when counting faces. EXAMPLE 2 Counting Faces, Edges, and Vertices SOLUTION

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

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

5. 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 for Examples 1, 2 and 3 GUIDED PRACTICE Classify the solid. Then tell whether it is a polyhedron.

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

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