Name ———————————————————————
SECTION
5
Date ————————————
Measurement
Composite figures are a combination of other figures such as squares and rectangles.
Areas can be added or subtracted to find the total area of a composite figure.
EXAMPLE 1
To find the area of the composite figure below, first draw a dashed line to divide it
into a square and a rectangle.
9 in.
Area of composite figure
5 Area of square 1 area of rectangle
3 in.
5.
5.MEASUREMENT
MEASUREMENT
5.
of Composite
1.Area
Perimeter
and Area
Lesson 5: Area of Composite Figures
square
rectangle
5 (3 in.)2 1 (6 in.)(5 in.)
5 in.
3 in.
5 9 in.2 1 30 in.2
6 in.
5 39 in.2
EXAMPLE 2
To find the area of the shaded figure, subtract
the area of the unshaded square from the total
area of the rectangle.
HINT
Composite figures can
be made with triangles,
parallelograms, trapezoids,
and other figures.
Area of shaded figure
Copyright © by McDougal Littell, a division of Houghton Mifflin Company.
5 Area of rectangle 2 area of square
14 cm
5 (6 cm)(14 cm) 2 (2 cm)2
5 84 cm2 2 4 cm2
6 cm
5 80 cm2
2 cm
6 cm
2 cm
14 cm
Practice: First Try
Find the area of the composite figure.
3 ft
1.
2.
1 cm
4 cm
6 ft
2 cm
3 ft
3 cm
18 ft
Find the area of each shaded figure.
3.
4.
2 in.
4 ft
10 ft
4 ft
1 in.
2 in.
6 in.
10 ft
McDougal Littell Middle School Math
Remediation Book Lesson 5.5
141
Name ———————————————————————
Date ————————————
5. MEASUREMENT
5. Area of Composite
Practice: Second Try
Find the area of each composite figure.
3 ft
1.
4 in.
2.
2 ft
10 yd
3.
4 in.
6 ft
10 yd
3 in.
10 yd
3 in.
3 yd
4 in.
4 yd
8 ft
1 yd
6 yd
4.
1m
5.
10 in.
5 in.
1m
6.
3 cm
4 cm
3m
10 in.
5m
3 cm
5 in.
5 cm
3 cm
4m
4 cm
2 cm
Find the area of each shaded figure.
5m
8.
9.
7 ft
8 ft
15 yd
4 ft
12 yd
8m
8m
9 ft
12 yd
2m
5m
Extend Your Skills
3 in.
10. Cara placed a large stamp on an envelope. The diagram shows
the dimensions of the stamp and the envelope. Explain two
ways to find the area of the envelope not covered by the
stamp. What is that area?
2 in.
5 in.
8 in.
Puzzle
Some sections of the figure at the right have the same area.
Name the sections with the same area and their area.
Then find the total area of the figure.
A
b!4
C
w!6
B
h!2
D
h!2
measurements are in feet.
142
McDougal Littell Middle School Math
Remediation Book Lesson 5.5
F
A!4
E
b!2
Copyright © by McDougal Littell, a division of Houghton Mifflin Company.
15 yd
7.
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