UNDERLYING SKILLS AND CONCEPTS:
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AF 1.4*0'
Use and$SSO\WKHDUHDDQGSHULPHWHUIRUPXODVIRUUHFWDQJOHVLQUHDOZRUOG
interpret formulas (e.g., area ! length # width or
DQGPDWKHPDWLFDOSUREOHPV)RUH[DPSOHILQGWKHZLGWKRIDUHFWDQJXODUURRPJLYHQWKH
A ! lw) to answer questions about quantities and their
DUHDRIWKHIORRULQJDQGWKHOHQJWKE\YLHZLQJWKHDUHDIRUPXODDVDPXOWLSOLFDWLRQ
relationships.
HTXDWLRQZLWKDQXQNQRZQIDFWRU
basic facts;
meaning of variable;
multiplication
Use Formulas for Perimeter
Perimeter is the distance around a figure. You can find perimeter by
adding the lengths of all the sides.
a
K
ey Ide
s
l
w
w
s
s
s
l
P!l"l"w"w
P!s"s"s"s
You can also use these formulas to find the perimeters of rectangles and squares.
Rectangle:
Square:
P ! 2l " 2w
P ! 4s
E x am p l E
1
P
P
P
P
!
!
!
!
2l " 2w
(2 # 6) " (2 # 4)
12 " 8
20 in.
w ! 4 in.
l ! 6 in.
E x am p l E
2
Find the perimeter of a square when s ! 6 feet.
P ! 4s
P!4#6
P ! 24 feet
How many feet around?
s ! 6 ft
page 220
Chapter 19 – Lesson 2
D – © CSL Associates, Inc. All rights reserved.
Find the perimeter of this rectangle.
Name
P RAC T I C E
Find the perimeter of each rectangle and square.
1.
w 4 ft
l 7 ft
2.
3.
l 10 ft
w 15 ft
22 feet
s 2 ft
50 feet
4. l 15 in.
5. l 24 ft
w 12 in.
6. s 10 in.
w 18 ft
54 in.
40 in.
84 ft
7. l 2.3 ft
8. s 12.5 ft
9. l 7.4 m
w 5.2 m
w 1.7 ft
50 ft
8 ft
D – © CSL Associates, Inc. All rights reserved.
8 feet
25.2 m
Solve each problem.
10. Charles is putting a fence in his
back yard for a dog run. He wants
the dog run to be 20 ft and 6 ft
wide. How many feet of fencing
does he need?
11. Carole bought a rug with a
perimeter of 36 feet. The rug is 8
feet wide. How long is it?
10 feet
52 feet
Math
Reasoning
Formulas for Perimeter
MR 2.3
12. Explain how using the formula for finding the perimeter of a square relates
to adding the lengths of the sides.
Since there are 4 sides to add that are the same length,
you can multiply the length of one side by 4.
Chapter 19 – Lesson 2
page 221
MCX94.HW.CL.G4.FM&Lesson.v211
8/2/04
19:16
Page 148
Name
…at home!
P RAC T I C E
Find the perimeter of each rectangle and square.
1.
2.
w 3 ft
l 8 ft
l 9 ft
w 13 ft
24 feet
42 feet
3. l 18 in.
4. l 23 ft
w 15 in.
w 11 ft
66 in.
68 ft
5. l 2.7 ft
6. s 9.5 ft
w 1.3 ft
Solve each problem.
7. Charles is putting a fence in his
back yard for a dog run. He wants
the dog run to be 30 ft long and
12 ft wide. How many feet of
fencing does he need?
8. Carol bought a rug with a
perimeter of 56 feet. The rug is 8
feet wide. How long is it?
20 feet
84 feet
Math
Reasoning
Formulas for Perimeter
MR 2.3
9. Explain how using the formula for finding the perimeter of a square relates
to adding the lengths of the sides.
Since there are 4 sides to add that are the same length,
you can multiply the length of one side by 4.
page 148
Home Resource and Homework
Chapter 19 Lesson 2
D – © CSL Associates, Inc. All rights reserved.
38 ft
8 ft
MCX94TEG4Ch01_32.v8.5.2 2/26/01 19:03 Page 407
Name
P RAC T I C E
Find the perimeter of each rectangle and square.
1.
w 4 ft
l 7 ft
2.
3.
l 10 ft
w 15 ft
22 feet
s 2 ft
50 feet
4. l 15 in.
5. l 24 ft
w 12 in.
6. s 10 in.
w 18 ft
54 in.
40 in.
84 ft
7. l 2.3 ft
8. s 12.5 ft
9. l 7.4 m
w 5.2 m
w 1.7 ft
50 ft
8 ft
D – © CSL Associates, Inc. All rights reserved.
8 feet
25.2 m
Solve each problem.
10. Charles is putting a fence in his
back yard for a dog run. He wants
the dog run to be 20 ft and 6 ft
wide. How many feet of fencing
does he need?
11. Carole bought a rug with a
perimeter of 36 feet. The rug is 8
feet wide. How long is it?
10 feet
52 feet
Math
Reasoning
Formulas for Perimeter
MR 2.3
12. Explain how using the formula for finding the perimeter of a square relates
to adding the lengths of the sides.
Since there are 4 sides to add that are the same length,
you can multiply the length of one side by 4.
Chapter 19 – Lesson 2
Student Book Page
page 221
Name
…at home!
P RAC T I C E
Find the perimeter of each rectangle and square.
1.
2.
w 3 ft
l 8 ft
l 9 ft
w 13 ft
24 feet
42 feet
3. l 18 in.
4. l 23 ft
w 15 in.
w 11 ft
66 in.
68 ft
5. l 2.7 ft
6. s 9.5 ft
w 1.3 ft
Solve each problem.
7. Charles is putting a fence in his
back yard for a dog run. He wants
the dog run to be 30 ft long and
12 ft wide. How many feet of
fencing does he need?
8. Carol bought a rug with a
perimeter of 56 feet. The rug is 8
feet wide. How long is it?
20 feet
84 feet
Math
Reasoning
Formulas for Perimeter
MR 2.3
9. Explain how using the formula for finding the perimeter of a square relates
to adding the lengths of the sides.
Since there are 4 sides to add that are the same length,
you can multiply the length of one side by 4.
page 148
Home Resource and Homework
Chapter 19 Lesson 2
D – © CSL Associates, Inc. All rights reserved.
38 ft
8 ft