• Vertex – A point at which two or more edges meet

• Edge – A line segment at which two faces intersect

• Face – A flat surface

Vertices, Edges, Faces

Vertices, Edges, Faces

• Name the following figures, and tell how many vertices, edges, and faces they have

Cross Sections

Definitions

• Polyhedron:

A solid that is made up of polygons (called faces) that enclose a single region in space.

Classify whether the 3-D figure is a polyhedron or not.

• Convex Polyhedron:

If any two points on the surface can be connected by a segment that lies on the interior, or on, the polyhedron.

Classify whether the 3-D figure is a convex polyhedron

or not.

• Regular Polyhedron:

A convex polyhedron in which all the faces are regular polygons.

Classify whether the 3-D figure is a regular convex

polyhedron or not.

• Cross Section:

The intersection of a plane and a solid.

Identify the cross section of the plane and the 3-D figure.

Cross Section

Pyramid

Plane

Classify whether the figure is a polyhedron. If it is, what kind and why? If it is not, why?

Describe the shape formed by the intersection of the plane and the 3-D figure.

If we cut the figure with a plane, parallel to the base, what shape would be formed?

If we cut the figure with a plane, perpendicular to the base, what shape

would be formed?