## Lesson: Finding Area and Volume

Developing the Concept

In this lesson the students will apply what they have learned about area to find the surface area of a solid figure. They will also learn how to find the volume of a rectangular prism.

**Materials:** tape, centimeter ruler, 4 cm x 3 cm x 2 cm rectangular box, 24 unit cubes (1 cm x 1 cm x 1 cm) for each group

**Preparation:** Use posterboard and tape to make the rectangular boxes. Label a face that measures 12 cm² *Top.* Label a face that measures 6 cm² *Side.* Label the face that measures 8 cm² *Front.* Distribute a ruler, 24 unit cubes, and a rectangular box to each group.

**Wrap-Up and Assessment Hints**

Ask students how the number of cubes in the bottom layer relates to the length and width of the bottom of the box. They should understand that the length times the width equals the number of cubes. Then ask them how the number of layers relates to the height of the box. They should understand that they are equal. To informally assess their understanding of perimeter, area, surface area, and volume, you may wish to provide students with the dimensions of another rectangular prism (3 in. x 4 in. x 6 in.) and have them find the surface area (108 in.²) and volume (72 in.^{3}) using the formulas. Have students work in groups and observe them as they work through the activity.