# Spectrum Math Grade 7 Chapter 5 Lesson 9 Answer Key Area: Rectangles

This handy Spectrum Math Grade 7 Answer Key Chapter 5 Lesson 5.9 Area: Rectangles provides detailed answers for the workbook questions

## Spectrum Math Grade 7 Chapter 5 Lesson 5.9 Area: Rectangles Answers Key

The area of a figure is the number of square units inside that figure. Area is expressed in square units or units2.

The area of a rectangle s the product of its length and its width.

A = l × w
A = 5 × 10 = 50 cm2

A = 5 × 5
A = 5 × 5 or 52
A = 25 cm2

If you know the area of a rectangle and either its length or its width, you can determine the unknown measure.

A = l × w
24 = 6 × w
$$\frac{24}{6}$$ = $$\frac{6w}{6}$$
4 = w
The width is 4 meters.

Find the unknown measure for each rectangle.

Question 1.
a.

area = ______________ cm2
A = 54 cm2

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
l = 6cm, w = 9cm
A = 6 × 9
A = 54 cm2

b.

area = _____________ m2
A = 84 m2

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
l = 8m, w = 10.5m
A = 8 × 10.5
A = 84 m2

c.

area = ______________ in.2
A = 56.25 in2

Explanation:
The area of a square is the product of its sides.
A = s x s
Given,
side = 7.5 in
A = 7.5 x 7.5
A = 56.25 in2

Question 2.
a.

length = _______________ ft.
length = 15 ft.

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
A = 150 ft2, l = 10 ft
150 = 10 × w
w = $$\frac{150}{10}$$
A = 15 ft

b.

width = _______________ m
width = 6 m

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
A = 72 m2, w = 12 m
72 = l × 12
l = $$\frac{72}{12}$$
l = 6m

c.

area = _______________ in.2
area = 135 in.2

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
l = 9 in, w = 15 in
A = 9 × 15
A = 135 in.2
Question 3.
a.

area = _____________ in.2
area = 165 in.2

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
l = 16.5 in, w = 10 in
A = 16.5 × 10
A = 165 in.2

b.

length = ______________ ft.
length = 12.5 ft.

Explanation:
The area of a rectangle s the product of its length and its width.
A = l × w
Given,
A = 62.5 ft2, w = 5 ft
62.5 = l × 5
l = $$\frac{62.5}{5}$$
l = 12.5 ft.

c.

side = ______________ m