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17.1
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Geometry and
Measurement—3.7.B
MATHEMATICAL PROCESSES
3.1.C, 3.1.E, 3.1.G
Model Perimeter
Essential Question
How can you find perimeter?
Hands
On
Investigate
Investigate
Perimeter is the distance around a figure.
Materials ■ geoboard ■ rubber bands
You can find the perimeter of a rectangle on a
geoboard or on dot paper by counting the number of
units on each side.
A. Make a rectangle on the geoboard that is 3 units on
two sides and 2 units on the other two sides.
B. Draw your rectangle on the dot paper below.
1 Unit
C. Write the length next to each side of your rectangle.
D. Add the number of units on each side.
_+_+_+_=_
© Houghton Mifflin Harcourt Publishing Company
E. So, the perimeter of the rectangle is _ units.
• How would the perimeter of the rectangle change if the
length of two of the sides was 4 units instead of 3 units?
Module 17
545
Make
Make Connections
Connections
Math Talk
You can also use grid paper to find the perimeter of figures
by counting the number of units on each side.
Start at the arrow and trace the perimeter. Begin counting
with 1. Continue counting each unit around the figure until
you have counted each unit.
A
Mathematical Processes
If a rectangle has a
perimeter of 12 units, how
many units wide and how
many units long could
it be? Explain.
B
1
1
1 Unit
1 Unit
Perimeter = _ units
Perimeter = _ units
Share
Share and
and Show
Show
Hands
On
Find the perimeter of the figure. Each unit is 1 centimeter.
2.
_ centimeters
546
_ centimeters
© Houghton Mifflin Harcourt Publishing Company
1.
Name
Problem
Problem Solving
Solving
Multi-Step What’s the Error?
3.
Kevin is solving perimeter problems. He counts
the units and says that the perimeter of this
figure is 18 units.
Look at Kevin’s solution.
A
Find Kevin’s error.
B
18 17
1
16 15
2
14
3
13
4
12
5
11
6
7
8
9 10
Perimeter = 18 units
Perimeter = _ units
• Use the grid on the right to find the correct perimeter of
© Houghton Mifflin Harcourt Publishing Company
the figure above.
4.
Apply Describe the error Kevin made.
5.
Use Diagrams Circle the places in the drawing of Kevin’s solution
where he made an error.
6.
Write Math
Explain how to find the length of each side of
a triangle with sides of equal length, and a perimeter of 27 inches.
Module 17 • Lesson 1
547
Mathematical Processes
M
Model ¥ Reason ¥ Communicate
M
Daily
Daily Assessment
Fill in the bubble completely to show your answer.
7.
8.
Joseph drew a game court on grid paper.
Each unit is 1 meter. What is the perimeter
of the game court?
A
18 meters
C
16 meters
B
15 meters
D
8 meters
Game Court
1 meter
Val is designing a dog park. She needs to
find the length for a fence around the park.
Each unit is 1 yard. What is the perimeter
of the park?
A
29 yards
C
47 yards
B
32 yards
D
34 yards
Park
1 yard
Multi-Step Greg is framing two rectangular
paintings. One painting has side lengths of
3 inches and 9 inches. The other painting
has side lengths of 4 inches and 6 inches.
How many inches of framing material will
Greg need for the two paintings?
A
48 inches
C
22 inches
B
51 inches
D
44 inches
TEXAS Test Prep
10.
548
Naomi drew this design for a quilt block. What
is the perimeter of the design?
A
12 units
C
14 units
B
16 units
D
18 units
© Houghton Mifflin Harcourt Publishing Company
9.
Geometry and Measurement—3.7.B
MATHEMATICAL PROCESSES 3.1.C, 3.1.E,
3.1.G
H o mewo rk
and Practice
17.1
Name
Model Perimeter
Find the perimeter of the figure. Each unit is 1 centimeter.
1.
2.
_ centimeters
_ centimeters
Problem
Problem Solving
Solving
3.
Alyssa says the perimeter of this figure
is 13 units. Describe the error Alyssa
Draw your own figure on the grid. Find
the perimeter.
10
13
1
4.
9
12 11
2
8
3
4
5
6
7
© Houghton Mifflin Harcourt Publishing Company
Perimeter = _ units
Module 17 • Lesson 1 549
TEXAS Test Prep
Lesson
Lesson Check
Check
Fill in the bubble completely to show your answer.
6.
7.
550
Paula drew this plan for a new
backyard shed. Each unit is 1 foot.
What is the perimeter of the shed?
A
24 feet
B
20 feet
C
18 feet
D
42 feet
Shed
1 foot
Andy drew this plan for a fence in
his yard. Each unit is 1 meter. What
is the perimeter of the fence?
A
18 meter
B
24 meter
C
22 meter
D
36 meter
Multi-Step Latoya sews a border
around two quilts. One quilt has side
lengths of 4 feet and 6 feet. Another
quilt has side lengths of 8 feet and
6 feet. How many feet of border does
she sew?
A
28 feet
B
20 feet
C
48 feet
D
42 feet
Fence
1 meter
8.
baseboards for two rectangular
rooms. One room has side lengths of
5 meters and 7 meters. The second
room has side lengths of 6 meters
and 9 meters. How many meters of
baseboard does Roland buy?
A
50 meters
B
30 meters
C
24 meters
D
54 meters
© Houghton Mifflin Harcourt Publishing Company
5.
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