1. Warm Up
Problem of the Day
Lesson Presentation
Lesson Quizzes

2. Warm Up
Find each product.
1. 8  12
2. 3
 6.3
 7 96 1 2 1 3 2 3
 5 18
59.22
24.5

3. Problem of the Day
How many 3 ft by 2 ft rectangles can you cut from one 8 ft by 4 ft rectangle? How much will be left over?
5 pieces; 2 ft2 left over

4. Learn to find the area of rectangles and other parallelograms.

5. Vocabulary
area

6. The area of a figure is the number of unit squares needed to cover the figure. Area is measured in units of length squared, or square units.

7. Example 1: Finding the Area of a Rectangle
Find the area of the rectangle.
4.5 in.
7.4 in.
A = lw
Use the formula.
A = 7.4 · 4.5
Substitute for l and w.
A = 33.3
Multiply.
The area of the rectangle is 33.3 in2.

8. Check It Out: Example 1
Find the area of the rectangle.
6.3 in.
8.2 in.
A = lw
Use the formula.
A = 8.2 · 6.3
Substitute for l and w.
A = 51.66
Multiply.
The area of the rectangle is in2.

9. Example 2: Finding Length or Width of a Rectangle
The area of a playing field is 1,470 ft2 and the length is 42 ft. What is the width of the field?
Use the formula for the area of a rectangle.
A = lw
1,470 = 42 · w
Substitute 1,470 for A and 42 for l.
1,470 42
42 · w 42 =
Divide both sides by 42 to isolate w.
35 = w
The width of the playing field is 35 ft.

10. Check It Out: Example 2
The area of a rectangular parking lot is 3,570 ft2 and the width is 70 ft. What is the length of the parking lot?
Use the formula for the area of a rectangle.
A = lw
3,570 = l · 70
Substitute 3,570 for A and 70 for w.
3,570 70
70 · w 70 =
Divide both sides by 70 to isolate w.
51 = l
The length of the parking lot is 51 ft.

12. Example 3: Finding the Area of a Parallelogram
Find the area of the parallelogram.
A = bh
8 m
A = 16
· 8
A = 128
16 m
The area of the parallelogram is
128 m2.

13. Check It Out: Example 3
Find the area of the parallelogram.
A = bh
6 cm
A = 12
· 6
A = 72
12 cm
The area of the parallelogram is
72 cm2.

14. Example 4: Measurement Application
A carpenter is laying a wood floor measuring 4 yd by 5 yd. How many square feet of flooring material does she need?
First draw and label a diagram. Look at the units. The wood floor is measured in yards, but the answer should be in square feet.
Convert yards to feet by using a conversion factor.
4 yd
5 yd

15. Example 4 Continued...
Now find the area in square feet.
Use the formula for the area of a rectangle.
A = lw
A = 15 · 12
Substitute 15 for l and 12 for w.
A = 180
Multiply.
She needs 180 ft2 of flooring material.

16. Check It Out: Example 4
A carpenter is laying a wood floor measuring 6 yd by 8 yd. How many square feet of flooring material does he need?
First draw and label a diagram. Look at the units. The wood floor is measured in yards, but the answer should be in square feet.
Convert yards to feet by using a conversion factor.
6 yd
8 yd

17. Check It Out: Example 4 Continued...
Now find the area in square feet.
Use the formula for the area of a rectangle.
A = lw
A = 24 · 18
Substitute 24 for l and 18 for w.
A = 432
Multiply.
He needs 432 ft2 of flooring material.

18. Lesson Quiz for Student Response Systems
Lesson Quizzes
Standard Lesson Quiz
Lesson Quiz for Student Response Systems 18

19. Find the area of each figure. 1. 2.
Lesson Quiz: Part I
Find the area of each figure. 3. 13 1 8
in2
105 or
24.5 ft2 4. 28 1 2
ft2 57 or
84 ft2

20. Lesson Quiz: Part II
5. Diego is building a rectangular platform measuring 36 in. by 54 in. What is the area of the platform in square feet?
13.5 ft2

21. Lesson Quiz for Student Response Systems
1. Identify the area of the rectangle.
A cm2
B cm2
C cm2
D. 81 cm2
9 cm
5.3 cm 21

22. Lesson Quiz for Student Response Systems
2. Identify the area of the parallelogram.
A. 144 in2
B. 72 in2
C. 50 in2
D. 25 in2 22

23. Lesson Quiz for Student Response Systems
3. Marcheline is building a wooden deck measuring 192 in. by 144 in. What is the area of the platform in square feet?
A. 192 ft2
B. 27,648 in2
C. 28 ft2
D. 32 ft2 23