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MG 1.4
Differentiate
between and use appropriate units of measures
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for two- and three-dimensional objects (i.e., find the perimeter,
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area, and volume).
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UNDERLYING SKILLS AND CONCEPTS:
recognize 2-dimensional figures; add
whole numbers; use customary and
metric units of length
Find Perimeter
Pe
You can find the perimeter of any
polygon by adding the lengths of all of its sides.
ri
ter
Perimeter is the distance around a
figure.
me
E x am p l E
Remember:
Perimeter measures
the distance around.
1
8 in.
Find the perimeter of this quadrilateral.
To find the perimeter, add the lengths of the sides.
Find 4 ! 5 ! 8 ! 10.
4 in.
5 in.
4 ! 5 ! 8 ! 10 " 27
The perimeter is 27 inches.
E x am p l E
10 in.
2
All of the sides of this polygon are the same. So, you can multiply
the number of sides by the length of one side to find the perimeter.
3 ft
There are 6 sides.
Each side measures 3 feet.
3 ft
3 ft
3 ft
3 ft
So, to find the perimeter, find 3 # 6.
3 # 6 " 18
The perimeter is 18 feet.
E x am p l E
3 ft
3
If you know the total perimeter, you can
find a missing measure. What is the length,
s, of this equilateral hexagon?
s"?
P " 48 in.
page 328
P " 48 inches " 6s
48
6s " $
6
6
s " 8 inches
The length is 8 inches.
Chapter 28 – Lesson 2
E – © CSL Associates, Inc. All rights reserved.
Find the perimeter of this equilateral polygon.
Name
P RAC T I C E
Find the perimeter of each figure.
1.
7 in.
2.
7 in.
18 ft
9 ft
7 in.
10 ft
11 ft
21 in.
3.
48 ft
4.
11.5 m
0.5 m
0.5 m
11.5 m
10 in.
10 in.
10 in.
10 in.
10 in.
10 in.
24 m
60 in.
5.
6.
10 m
10 m
20 m
20 m
7 ft
48 ft
14 ft
7 ft
30 ft
E – © CSL Associates, Inc. All rights reserved.
32 m
106 ft
92 m
7. Francisco built a rectangular game
board that was 0.75 meter long and
0.4 meter wide. What is the
perimeter of the board?
2 0.75 1.5
2 0.40 0.8
2.3 meters
Math
Reasoning
8. Georgina wanted to put tape around the
outside of her science fair display.
The project was displayed on a
cardboard hexagon, 48 cm on
each side. Is 3 meters of tape enough?
Explain.
Yes. 6 48 cm 288 cm or
2.88 meters
Perimeter
MR 2.2
9. Joy has a 30-inch piece of wood to make a picture frame. Does she have enough wood
to put a frame on a picture that is 8 inches by 10 inches? Explain.
No. The perimeter of the picture is 36 in., so she doesn’t
have enough wood.
Chapter 28 – Lesson 2
page 329
MCX94.HW.CL.G5.FM&Lesson.v211
8/2/04
18:03
Page 220
Name
…at home!
P RAC T I C E
Find the perimeter of each figure.
1.
5 in.
2.
5 in.
5 in.
11 ft
9 ft
10 ft
9 ft
10 ft
11 ft
15 in.
60 ft
4.
8.5 m
3. 0.5 m
12 in.
12 in.
0.5 m
8.5 m
12 in.
12 in.
12 in.
12 in.
18 m
72 in.
5.
6.
14 ft
5m
10 m
10 m
7 ft
30 ft
7 ft
16 m
7 ft
7 ft
14 ft
30 ft
46 m
116 ft
7. Jamal drew a model airplane design on
8. Eva wanted to put tape around the
a piece of paper that was 0.35 meter
long and 0.3 meter wide. What is the
perimeter of the paper?
outside of her science fair display.
The project was displayed on a
cardboard octagon, 24 cm on each side.
Is 3 meters of tape enough? Explain.
2 0.35 0.7
2 0.30 0.6
1.3 meters
Yes. 8 24 cm 192 cm or
1.92 meters 3 meters
Math
Reasoning
Perimeter
MR 2.2
9. Melany has a 48-inch piece of wood to make a picture frame. Does she have
enough wood to put a frame on a picture that is 8 inches by 10 inches? Explain.
Yes. (8 2) (10 2) 16 20 36; 36 48. The perimeter of the
picture frame is 36 in., so she has enough wood.
page 220
Home Resource and Homework
Chapter 28 Lesson 2
E – © CSL Associates, Inc. All rights reserved.
5m
MCX94TEG5CH01_32.v7.4.2 2/24/01 19:50 Page 605
Name
P RAC T I C E
Find the perimeter of each figure.
1.
7 in.
2.
7 in.
18 ft
9 ft
7 in.
10 ft
11 ft
21 in.
3.
48 ft
4.
11.5 m
0.5 m
0.5 m
11.5 m
10 in.
10 in.
10 in.
10 in.
10 in.
10 in.
24 m
60 in.
5.
6.
10 m
7 ft
10 m
20 m
48 ft
14 ft
20 m
7 ft
30 ft
E – © CSL Associates, Inc. All rights reserved.
32 m
106 ft
92 m
7. Francisco built a rectangular game
board that was 0.75 meter long and
0.4 meter wide. What is the
perimeter of the board?
2 0.75 1.5
2 0.40 0.8
2.3 meters
Math
Reasoning
8. Georgina wanted to put tape around the
outside of her science fair display.
The project was displayed on a
cardboard hexagon, 48 cm on
each side. Is 3 meters of tape enough?
Explain.
Yes. 6 48 cm 288 cm or
2.88 meters
Perimeter
MR 2.2
9. Joy has a 30-inch piece of wood to make a picture frame. Does she have enough wood
to put a frame on a picture that is 8 inches by 10 inches? Explain.
No. The perimeter of the picture is 36 in., so she doesn’t
have enough wood.
Chapter 28 – Lesson 2
Student Book Page
page 329
Name
…at home!
P RAC T I C E
Find the perimeter of each figure.
1.
5 in.
2.
5 in.
5 in.
11 ft
9 ft
10 ft
9 ft
10 ft
11 ft
15 in.
60 ft
4.
8.5 m
3. 0.5 m
12 in.
12 in.
0.5 m
8.5 m
12 in.
12 in.
12 in.
12 in.
18 m
72 in.
5.
6.
5m
10 m
10 m
7 ft
30 ft
7 ft
16 m
7 ft
7 ft
14 ft
30 ft
46 m
116 ft
7. Jamal drew a model airplane design on
8. Eva wanted to put tape around the
a piece of paper that was 0.35 meter
long and 0.3 meter wide. What is the
perimeter of the paper?
outside of her science fair display.
The project was displayed on a
cardboard octagon, 24 cm on each side.
Is 3 meters of tape enough? Explain.
2 0.35 0.7
2 0.30 0.6
1.3 meters
Yes. 8 24 cm 192 cm or
1.92 meters 3 meters
Math
Reasoning
Perimeter
MR 2.2
9. Melany has a 48-inch piece of wood to make a picture frame. Does she have
enough wood to put a frame on a picture that is 8 inches by 10 inches? Explain.
Yes. (8 2) (10 2) 16 20 36; 36 48. The perimeter of the
picture frame is 36 in., so she has enough wood.
page 220
Home Resource and Homework
Chapter 28 Lesson 2
E – © CSL Associates, Inc. All rights reserved.
5m
14 ft