7th Grade Math

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Composite Figures

PART A B C

Multi-Part

Lesson 3

606 Volume and Surface Area

Main Idea

Find the volume and

surface area of

composite figures.

Volume and Surface Area

of Composite Figures

BASKETS The Rockwell family uses the basket

shown on their staircase. Mrs. Rockwell

would like to make a duplicate for extra

storage. She needs to determine the

surface area to find how much material

she will need and the volume to find how

much storage it has.

1. What three-dimensional figures make up the basket?


2. What method could you use to find the volume and
   surface area of the basket?

The basket above is made up of two rectangular prisms. The volume

of a composite figure can be found by separating the figure into solids

whose volumes you know how to find.

Volume of a Composite Figure

BASKETS Find the volume of the

16 in.

16 in.

8 in.

8 in.

6 in.

staircase basket above.

Find the volume of each prism.

16 in.

8 in.

6 in.

8 in.

8 in.

6 in.

V = wh V = wh

V = 8 · 6 · 16 or 768 V = 8 · 6 · 8 or 384

The volume is about 768 + 384 or

1,152 cubic inches.

a. Find the volume of the

9 cm

7 cm

12 cm

1 cm 1 cm

6 cm

composite figure.

sket

up the basket?

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