CCSS
G3.MD.8
Solve real world
mathematical
problems
involving perimeters
MG 1.3
Find the perimeter
of a and
polygon
with integer
sides.
of polygons, including finding the perimeter given the side lengths, finding an unknown
side length, and exhibiting rectangles with the same perimeter and different areas or with
the same area and different perimeters.
UNDERLYING SKILLS AND CONCEPTS:
measure length
Find Perimeter
a
K
ey Ide
The perimeter of a figure is
the distance around the figure.
To find perimeter of a figure:
• find the length of each side, then,
• add the lengths together.
P
The total length is the perimeter.
Peri
E x am p l E
meter
1
Find the perimeter of the rectangle.
You can count the units along the outside
of the rectangle to find the perimeter.
E x am p l E
C – © CSL Associates, Inc. All rights reserved.
The perimeter of this rectangle is 14 units.
2
Find the perimeter of the polygon.
Add the lengths of all the sides.
4 2 1 1 3 3 14
The perimeter of the polygon is 14 units.
Note: the perimeter remains the same if the
missing top-corner is put back (see Example 1).
So, two shapes with the same perimeter can
cover a different number of squares.
They have the same perimeter but different area.
page 326
Chapter 28 – Lesson 1
Name
P RAC T I C E
Find the perimeter of each figure.
1.
2.
14 units
4.
3.
16 units
5.
16 units
18 units
6.
28 units
24 units
C – © CSL Associates, Inc. All rights reserved.
Solve. Explain how you decided.
7. Mr. Louis is shipping a box. It is
12 inches wide and 20 inches long.
Use the table. What will he
probably pay to ship the box?
$10.00. The perimeter of the box
is 12122020 64 inches
Math
Reasoning
Shipping Rates
Maximum Perimeter
48 inches
60 inches
92 inches
108 inches
Cost
$5.50
$6.75
$10.00
$12.45
Perimeter Puzzle
MR 2.2
8. I am a pentagon. My perimeter is 35 inches.
Each of my sides is the same length.
How long is one of my sides? Explain how you decided.
7 inches. A pentagon has 5 sides. So divide the perimeter
by 5 to find the length of one equal side. 35 5 7
Chapter 28 – Lesson 1
page 327
MCX94.HW.CL.G3.FM&Lesson.v211
8/3/04
13:57
Page 218
Name
…at home!
P RAC T I C E
Find the perimeter of each figure.
1.
2.
12 units
4.
3.
12 units
18 units
5.
16 units
6.
26 units
28 units
7. Mr. Johnson is shipping a box. It is
12 inches wide and 18 inches long.
Use the table. What will he
probably pay to ship the box?
$6.75. The perimeter of the box
is 12121818 60 inches
Math
Reasoning
Shipping Rates
Maximum Perimeter
48 inches
60 inches
92 inches
108 inches
Cost
$5.50
$6.75
$10.00
$12.45
Perimeter Puzzle
MR 2.2
8. I am a hexagon. My perimeter is 36 inches.
Each of my sides is the same length.
How long is one of my sides? Explain how you decided.
6 inches. A hexagon has 6 sides. So divide the perimeter
by 6 to find the length of one equal side. 36 6 6
page 218
Home Resource and Homework
Chapter 28 Lesson 1
C – © CSL Associates, Inc. All rights reserved.
Solve. Explain how you decided.
MCX94TEG3Ch01_32.v8.9.3 2/21/01 14:51 Page 601
Name
P RAC T I C E
Find the perimeter of each figure.
1.
2.
3.
14 units
4.
16 units
18 units
5.
6.
16 units
28 units
24 units
C – © CSL Associates, Inc. All rights reserved.
Solve. Explain how you decided.
7. Mr. Louis is shipping a box. It is
12 inches wide and 20 inches long.
Use the table. What will he
probably pay to ship the box?
$10.00. The perimeter of the box
is 12122020 64 inches
Math
Reasoning
Shipping Rates
Maximum Perimeter
48 inches
60 inches
92 inches
108 inches
Cost
$5.50
$6.75
$10.00
$12.45
Perimeter Puzzle
MR 2.2
8. I am a pentagon. My perimeter is 35 inches.
Each of my sides is the same length.
How long is one of my sides? Explain how you decided.
7 inches. A pentagon has 5 sides. So divide the perimeter
by 5 to find the length of one equal side. 35 5 7
Chapter 28 – Lesson 1
Student Book Page
page 327
Name
…at home!
P RAC T I C E
Find the perimeter of each figure.
1.
2.
12 units
4.
3.
12 units
18 units
5.
16 units
6.
26 units
28 units
7. Mr. Johnson is shipping a box. It is
12 inches wide and 18 inches long.
Use the table. What will he
probably pay to ship the box?
$6.75. The perimeter of the box
is 12121818 60 inches
Math
Reasoning
Shipping Rates
Maximum Perimeter
48 inches
60 inches
92 inches
108 inches
Cost
$5.50
$6.75
$10.00
$12.45
Perimeter Puzzle
MR 2.2
8. I am a hexagon. My perimeter is 36 inches.
Each of my sides is the same length.
How long is one of my sides? Explain how you decided.
6 inches. A hexagon has 6 sides. So divide the perimeter
by 6 to find the length of one equal side. 36 6 6
page 218
Home Resource and Homework
Chapter 28 Lesson 1
C – © CSL Associates, Inc. All rights reserved.
Solve. Explain how you decided.