A three dimensional figure that has three dimensions: length, width, and height.

cubecylinder

cone

Rectangular prism

pyramid

Some Vocabulary

• Polyhedron: A 3-D figure whose faces are all polygons.

• Base: The face that is used to name a polyhedron.

Naming Polyhedrons

Step 1: Identify the base of the solid. It will be used to name the polyhedron.

Hint: It will be the name of a polygon.

Step 2: Determine if the object is a prism or pyramid.

Step 3: Name the polyhedron.

Naming Solids: Step 1

Identify the base of the solid. It will be used to name the polyhedron.

Hint: It will be the name of a polygon.

Example:

There is one base, and it is a pentagon.

Naming Solids: Step 2

Determine if the object is a prism or pyramid.

Naming Solids: Step 2

Example:

There is one base that is a polygon and there are five triangular faces, which makes it a pyramid.

Naming Solids: Step 3

Name the polyhedron

Example:

Base: Pentagon

Faces: Pyramid

Name: Pentagonal Pyramid

Combine what you found in Steps 1 and 2 to name the figure.

Other three-dimensional figures include cylinders, cones, and spheres. These figures are not polyhedrons because they are not made of faces that are all polygons.

Not Polyhedrons

Cylinders Cones Spheres

Cross Sections•Video

Let’s ReviewLet’s Review

Right rectangular prism Plane

Let’s ReviewCore Lesson

Vocabulary: Cross sectionThe two-dimensional shape that results from cutting a three-dimensional shape

with a plane

Circle

Let’s ReviewCore Lesson

Cutting a right rectangular prism with a plane parallel to its base

Rectangle

Let’s ReviewCore Lesson

Cutting a right rectangular prism with a plane perpendicular to its base

Rectangle

Let’s ReviewCore Lesson

Cutting a right rectangular pyramid with a plane parallel to its base

Rectangle

Let’s ReviewCore Lesson

Cutting a right rectangular pyramid with a plane perpendicular to its base

and containing its vertex

vertex

Triangle

•Practice!