&&66
**Differentiate
)LQGWKHDUHDRIULJKWWULDQJOHVRWKHUWULDQJOHVVSHFLDO
MG 1.4
between and use appropriate units of measures
TXDGULODWHUDOVDQGSRO\JRQVE\FRPSRVLQJLQWRUHFWDQJOHVRUGHFRPSRVLQJLQWRWULDQJOHV
for, two- and three-dimensional objects (e.g., find the perimeter,
DQGRWKHUVKDSHVDSSO\WKHVHWHFKQLTXHVLQWKHFRQWH[WRIVROYLQJUHDOZRUOGDQG
area, and volume).
PDWKHPDWLFDOSUREOHPV
UNDERLYING SKILLS AND CONCEPTS:
write equations for problems;
solve for the unknown;
add and subtract integers
Solve Problems Using Formulas
You can use formulas to solve measurement problems.
The formula for finding the perimeter of a rectangle is p ! 2l " 2w.
The formula for finding the area of a rectangle is A !l # w
The formula for finding the perimeter of a square is p ! 4s.
The formula for finding the area of a square is A ! s2.
E x am p l E
1
Find the perimeter of a rectangle that is 12 inches long and 10 inches wide.
Use p ! 2l " 2w
Substitute 12 for l and 10 for w.
p ! (2 # 12) " (2 # 10)
p ! 44
The perimeter is 44 inches.
l ! 12 in.
Multiply.
Add.
w ! 10 in.
E x am p l E
2
Find the area of a rectangle that is 12 inches long and 10 inches wide.
Use A ! l # w
A ! 12 # 10
Substitute 12 for l and 10 for w.
A ! 120
Multiply.
The area is 120 square units.
E x am p l E
l ! 12 in.
w ! 10 in.
3
Find the area of a square if the side of the square is 6 feet.
Use A ! s2
A ! 62 Substitute 6 for s.
s ! 6 ft
A ! 36 Multiply.
The area is 36 square feet.
page 326
Chapter 28 – Lesson 1
E – © CSL Associates, Inc. All rights reserved.
p ! 24 " 20
Name
P RAC T I C E
Find the perimeter of each figure. Use p 2l 2w.
1. l 9
2. l 15
3. l 18
4. l 22
28
50
60
64
7. l 20
8. l 25
w5
w 10
w 12
w 10
Find the area of each rectangle. Use A l w.
5. l 10
6. l 12
60
72
w6
w6
w 12
240
w8
200
Find the area of of each square. Use A s2.
9. s 3
10. s 4
9
16
11. s 9
81
12. s 12
144
E – © CSL Associates, Inc. All rights reserved.
Find the missing value. Show your work.
13.
Area = 144 square units
w?
l 16
Math
Reasoning
144 16 w
144
w
16
9w
Formulas
MR 2.4
14. To find the perimeter of a rectangle, Kimberly used the formula
p 2(l w). Will she get the same answer if uses p 2l 2w?
Explain why or why not.
Yes, she would get the same answer. If you use the distributive
property 2(l w) 2l 2w.
Chapter 28 – Lesson 1
page 327
MCX94.HW.CL.G5.FM&Lesson.v211
8/2/04
18:03
Page 218
Name
…at home!
P RAC T I C E
Find the perimeter of each figure. Use p 2l 2w.
1. l 8
2. l 16
3. l 15
4. l 12
26
52
54
64
7. l 20
8. l 25
w5
w 10
w 12
w 20
Find the area of each rectangle. Use A l w.
5. l 8
6. l 14
48
84
w6
w6
w 15
300
w4
100
Find the area of of each square. Use A s 2.
9. s 6
10. s 5
36
11. s 4
16
25
12. s 11
121
13.
Area = 144 square units
w?
144
w
18
8w
l 18
Math
Reasoning
144 18 w
Formulas
MR 2.4
14. To find the area of a square, Chi-Lin used the formula
a s2. Will she get the same answer if uses a s s?
Explain why or why not.
Yes, she would get the same answer.
She can use either formula.
page 218
Home Resource and Homework
Chapter 28 Lesson 1
E – © CSL Associates, Inc. All rights reserved.
Find the missing value. Show your work.
MCX94TEG5CH01_32.v7.4.2 2/24/01 19:50 Page 601
Name
P RAC T I C E
Find the perimeter of each figure. Use p 2l 2w.
1. l 9
2. l 15
3. l 18
4. l 22
28
50
60
64
7. l 20
8. l 25
w5
w 10
w 12
w 10
Find the area of each rectangle. Use A l w.
5. l 10
6. l 12
60
72
w6
w6
w 12
240
w8
200
Find the area of of each square. Use A s2.
9. s 3
10. s 4
9
11. s 9
81
16
12. s 12
144
E – © CSL Associates, Inc. All rights reserved.
Find the missing value. Show your work.
13.
Area = 144 square units
w?
144
w
16
l 16
Math
Reasoning
144 16 w
9w
Formulas
MR 2.4
14. To find the perimeter of a rectangle, Kimberly used the formula
p 2(l w). Will she get the same answer if uses p 2l 2w?
Explain why or why not.
Yes, she would get the same answer. If you use the distributive
property 2(l w) 2l 2w.
Chapter 28 – Lesson 1
Student Book Page
page 327
Name
…at home!
P RAC T I C E
Find the perimeter of each figure. Use p 2l 2w.
1. l 8
2. l 16
3. l 15
4. l 12
26
52
54
64
7. l 20
8. l 25
w5
w 10
w 12
w 20
Find the area of each rectangle. Use A l w.
5. l 8
6. l 14
48
84
w6
w6
w 15
300
w4
100
Find the area of of each square. Use A s 2.
9. s 6
10. s 5
36
11. s 4
16
25
12. s 11
121
13.
Area = 144 square units
w?
144
w
18
8w
l 18
Math
Reasoning
144 18 w
Formulas
MR 2.4
14. To find the area of a square, Chi-Lin used the formula
a s2. Will she get the same answer if uses a s s?
Explain why or why not.
Yes, she would get the same answer.
She can use either formula.
page 218
Home Resource and Homework
Chapter 28 Lesson 1
E – © CSL Associates, Inc. All rights reserved.
Find the missing value. Show your work.