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 units^{2}.

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

A = l × w

A = 5 × 10 = 50 cm^{2}

A = 5 × 5

A = 5 × 5 or 5^{2}

A = 25 cm^{2}

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 = ______________ cm^{2}

Answer:

A = 54 cm^{2}

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 cm^{2}

b.

area = _____________ m^{2}

Answer:

A = 84 m^{2}

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 m^{2}

c.

area = ______________ in.^{2}

Answer:

A = 56.25 in^{2}

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 in^{2}

Question 2.

a.

length = _______________ ft.

Answer:

length = 15 ft.

Explanation:

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

A = l × w

Given,

A = 150 ft^{2}, l = 10 ft

150 = 10 × w

w = \(\frac{150}{10}\)

A = 15 ft

b.

width = _______________ m

Answer:

width = 6 m

Explanation:

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

A = l × w

Given,

A = 72 m^{2}, w = 12 m

72 = l × 12

l = \(\frac{72}{12}\)

l = 6m

c.

area = _______________ in.^{2}

Answer:

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}

Answer:

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.

Answer:

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 ft^{2}, w = 5 ft

62.5 = l × 5

l = \(\frac{62.5}{5}\)

l = 12.5 ft.

c.

side = ______________ m

Answer:

side = 11 m

Explanation:

The area of a square is the product of its sides.

A = s x s

Given,

A = 121 m^{2},

121 = s^{2}

s^{2} = 121

s = 11 m.