C

Multi-Part Lesson

8-3PART

Area of Composite Shapes

A B

Main IdeaI will find the area of composite shapes.

New Vocabulary composite shape

Find Areas of Composite ShapesA composite shape is made up of two or more shapes. To find the area of a composite shape, break it into smaller parts.

POOLS Drew is staying at a hotel that has the swimming pool shown. Drew wants to know the area of the pool. Find the area of the swimming pool at Drew’s hotel.

Step 1 Break up the figure into smaller parts. Look for rectangles and squares.

Step 2 Find the area of each part.

Step 3 Add the areas.

The area is 72 + 100 or 172 square meters.

398 Chapter 8 Find Area

SquareA = side × sideA = s × sA = 10 m × 10 mA = 100 sq m

RectangleA = length (base) × width (height)A = � × wA = 12 m × 6 m

A = 72 sq m

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Area of a Composite Shape

Find the area of the compositeshape.

Step 1 Break up the shape into smaller parts. Look for rectangles and squares. This shape can be broken into 1 rectangle and 2 squares.

Step 2 Find the area of each part.

Rectangle Square A = length × width A = side × side A = 12 ft × 2 ft A = 3 ft × 3 ft A = 24 square feet A = 9 square feet

Step 3 Add the areas. 24 + 9 + 9 = 42

So, the area of the shape is 42 square feet.

Area of a Composite Shape

Find the area of each shape. See Examples 1 and 2 (pp. 398–399)

1. 2. 3.

4. What is the area of the garden shown at the right?

5. Refer to Exercise 4. When finding the area of the garden, what two shapes did you look for?

Lesson 8-3 Area of Composite Shapes 399

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Find the area of each shape. See Examples 1 and 2 (pp. 398–399)

6. 7. 8.

9. 10. 11.

12. Courtney is playing miniature golf. What is the area of the entire shape?

13. What is the area of the desktop?

PRACTICEEXTRASee page R25.PRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEPRACTICEEXTRA

See page R25.

The builders of Fort Jefferson at Dry Tortugas National Park in Florida began in 1846. It was supposed to house large cannons, but was never completed.

14. Draw a picture to show how you could decompose a hexagon to find the area of Fort Jefferson.

15. Trace a hexagon pattern block on a centimeter grid paper. Count the squares to estimate the area.

400 Chapter 8 Find Area

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Practice

16. OPEN ENDED Draw and label two composite shapes that have the same area but have different perimeters.

17. CHALLENGE Find the area of the shaded shape in units.

18. Create a word problem about a real-world situation involving perimeter and area of a composite shape.

Choose the better estimate. (Lesson 8-2E)

21. doormat 22. dining room table 23. bathroom tile6 square inches or 2 square feet or 16 square inches or 6 square feet 2 square yards 16 square yards

24. Pia plays 32 minutes each soccer game and has 15 games during the season. Her older sister plays 28 minutes each soccer game and has 18 games in her season. How many more minutes does Pia’s sister play than Pia? (Lesson 8-2D)

Lesson 8-3 Area of Composite Shapes 401

19. Which equation below represents the area (A) of the square in square inches?

A. 7 = A × 7

B. A = (2 × 7) + (2 × 7)

C. A = 7 × 7

D. A = 7 × 4

20. Which statement about the shape is true?

F. The area is equal to the perimeter.

G. The perimeter is greater than the area.

H. The perimeter 38 centimeters.

I. The area is 48 square centimeters.

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