1. Three- Dimensional Figures #37

2. A polyhedron is a three-dimensional object with flat surfaces, called faces, that are polygons. When two faces of a three-dimensional figure share a side, they form an edge. A point at which three or more edges meet is a vertex (plural: vertices). VOCABULARY

3. Example 1: Identifying Faces, Edges, and Vertices Identify the number of faces, edges, and vertices on each three-dimensional figure. A. B.

4. Example 2 Identify the number of faces, edges, and vertices on each three-dimensional figure. A. B.

5. A prism is a polyhedron with two congruent, parallel bases, and other faces that are all parallelograms. A prism is named for the shape of its bases. A cylinder also has two congruent, parallel bases, but bases of a cylinder are circular. A cylinder is not a polyhedron because not every surface is a polygon. VOCABULARY

6. A pyramid has one polygon-shaped base and three or more triangular faces that share a vertex. A pyramid is named for the shape of its base. A cone has a circular base and a curved surface that comes to a point. A sphere has no base and one curved surface. All points on the surface are the same distance from a point called the center of the sphere. VOCABULARY

7. Cones and spheres are not polyhedrons because they have curved surfaces. Helpful Hint

8. Example 3: Naming Three-Dimensional Figures Name the three-dimensional figure represented by the object.

9. Example 4: Naming Three-Dimensional Figures Name the three-dimensional figure represented by the object.

10. Example 5: Naming Three-Dimensional Figures Name the three-dimensional figure represented by the object.

11. Example 6 Name the three-dimensional figure represented by the object.

12. Example 7 Name the three-dimensional figure represented by the object.

13. Example 8 Name the three-dimensional figure represented by the object.