What is the true number of faces of a rectangular prism?

In this lesson you will learn how to analyze rectangular prisms by locating pairs of congruent faces.

Let’s Review Two figures are congruent when they are exactly the same shape and size. congruent: not congruent:

Let’s Review Two faces on a 3D solid are parallel when they never intersect. parallel: not parallel:

Let’s Review A prism is a three-dimensional figure with two parallel and congruent polygonal bases.

Core Lesson There are three different types of rectangular prisms:

Let’s Review Core Lesson Some prisms have 3 different pairs of matching, congruent faces.

Let’s Review Core Lesson

Let’s Review Core Lesson Some prisms have 2 different sizes of congruent faces.

Let’s Review Core Lesson

Let’s Review Core Lesson Some prisms have 1 face size. (These prisms are called cubes.)

Let’s Review Core Lesson

Let’s Review Core Lesson Some rectangular prisms have 3 different pairs of matching, congruent faces. Some rectangular prisms have 2 different sizes of congruent faces. Some prisms (cubes) have 1 face size.

In this lesson you learned how to analyze rectangular prisms by locating pairs of congruent faces.

Let’s Review Guided Practice Describe the difference between the gift packages that you see, below. Draw a net for each gift. The first gift has two face sizes. There are squares on top/bottom, and rectangles on the four sides. This gift is a cube, so it has 6 faces that are all the same size.

Let’s Review Extension Activities Below is a sample of each of the three types of rectangular prisms. Draw the net for each of these prisms, paying careful attention to the different sizes of the rectangular faces.

Let’s Review Extension Activities Look around your classroom. Locate one of each of the different types of rectangular prisms that you learned about, in this lesson. Use your observations to complete the chart, below. (For example: You might write “dice” as an example of a prism with 1 face size.) When you are finished, you and a partner will describe to one another why you selected each object. 3 face sizes = 2 face sizes = 1 face size = # face sizes:object:

Let’s Review Quick Quiz How many different sizes of rectangular faces are there on a cube? Prove your answer by drawing a net. How many different sizes of rectangular faces are there on your mattress? Prove your answer by drawing a net.