All the solutions provided inÂ **McGraw Hill My Math Grade 3 Answer Key PDF Chapter 13 Lesson 6 Area of Rectangles **will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 3 Answer Key Chapter 13 Lesson 6 Area of Rectangles

**Math in My World**

**Example 1**

A park manager is building a small rectangular playground. St will be 10 meters by 7 meters. Its area will be covered with shredded tires. What is the area of the playground that will be covered with shredded tires?

One Way:

Tile a rectangle.

1. Tile a rectangle with unit squares. It is squares long and 7 unit squares wide.

Each unit square represents one square meter.

2. Count the unit squares.

There are ______________ unit squares.

Another Way:

Multiply the side lengths.

Multiply the length by the width.

10 Ă— 7 = _____________ The length is 10 meters and the width is 7 meters.

Area is measured in square units. In this case, it is measured in square meters.

So, the area of the playground is ______________ square meters.

Check: You can check by using repeated addition to count the number of squares in each row.

10 + 10 + 10 + 10 + 10 + 10 + 10 = ______________

Answer:

Multiply the side lengths.

Multiply the length by the width.

10 Ă— 7 = 70. The length is 10 meters and the width is 7 meters.

The area is measured in square units. In this case, it is measured in square meters.

So, the area of the playground is 70 square meters.

Check: You can check by using repeated addition to count the number of squares in each row.

10 + 10 + 10 + 10 + 10 + 10 + 10 = 70

There are **70** unit squares.

**Example 2**

Find the area of the rectangle.

Replace each symbol with its value.

A = l Ă— w Use the area formula.

A = 9 Ă— 5 The length is 9 feet and the width is 5 feet.

45 = 9 Ă— 5 Multiply.

Area is measured in square units. In this case, it is measured in square feet.

So, the area is _________________ square feet.

Answer:

A = l Ă— w Use the area formula.

A = 9 Ă— 5 The length is 9 feet and the width is 5 feet.

45 = 9 Ă— 5 Multiply.

So, the area is 45 square feet.

**Talk Math**

Explain two ways to find the area of a rectangle.

Answer:

Method 1: If you know the length and the breadth of the rectangle, then to find the area of the rectangle just multiply length times breadth or breadth times length and write the answer with the square of units.

Method 2: If you have the width and the diagonal of the rectangle then similar to method 2. find the length of the rectangle and then apply method 1 to find the area of the rectangle.

**Guided Practice**

**Find the area of each rectangle.**

Question 1.

The area is _______________ square inches.

Answer:

Given,

l = 6 in.

w = 2 in.

Area of the rectangle = lw

A = 6 Ă— 2

A = 12 sq. in.

Question 2.

The area is _______________ square meters.

Answer:

Given,

s = 3m

Area of the square = s Ă— s

A = 3 Ă— 3

A = 9 sq. meter

**Independent Practice**

**Find the area of each rectangle.**

Question 3.

____________ square feet

Answer:

Given,

l = 4 ft

w = 7ft

Area of the rectangle = lw

A = 4 Ă— 7

A = 28 sq. ft

Question 4.

____________ square meters

Answer:

Given,

l = 5m

w = 4m

Area of the rectangle = lw

A = 5 Ă— 4

A = 20 sq. m

Question 5.

Answer:

Given,

l = 8 in.

w = 6 in.

Area of the rectangle = lw

A = 8 Ă— 6

A = 48 sq. in

Question 6.

Answer:

Given,

l = 10 cm

w = 4 cm

Area of the rectangle = lw

A = 10 Ă— 4

A = 40 sq. cm

Question 7.

A rectangle has an area of 42 square meters. Which could represent the length and width of this rectangle? Circle it.

7 meters and 6 meters

6 meters and 8 meters

Answer: 7 meters and 6 meters

Explanation:

A rectangle has an area of 42 square meters.

A = 7 Ă— 6 = 42 sq. meter

**Algebra Find the unknown side. Use the area formula.**

Question 8.

The area is 9 square yards.

A = l Ă— w

9 = ____________ Ă— 1

The unknown is _____________ yards.

Answer:

The area is 9 square yards.

A = l Ă— w

9 = l Ă— 1

l = 9

The unknown is 9 yards.

Question 9.

The area is 6 square feet.

A = l Ă— w

6 = 3 Ă— ______________

The unknown is _______________ feet.

Answer:

Given,

The area is 6 square feet.

A = l Ă— w

6 = 3 Ă— w

w = 6/3

w = 2

The unknown is 2 feet.

**Problem Solving**

Question 10.

**Mathematical PRACTICE** Use Math Tools Andrea is making a quilt in the shape of a rectangle. The length of the quilt will be 6 feet and the width will be 5 feet. What is the area of the quilt she will make? Write an equation to solve.

Answer:

Given,

The length of the quilt will be 6 feet and the width will be 5 feet.

A = 6 Ă— 5 = 30 sq. ft

Question 11.

A throw rug is 8 feet long and 4 feet wide. It is in a rectangular room with an area of 110 square feet. How much of the room is not covered by the rug?

Answer:

A throw rug is 8 feet long and 4 feet wide.

A = 8 Ă— 4 = 32 sq. ft

It is in a rectangular room with an area of 110 square feet.

110 – 32 = 78 sq. ft

**HOT Problems**

Question 12.

**Mathematical PRACTICE** Use Number Sense A rectangle has side lengths of 5 centimeters and 3 centimeters. If the side lengths are doubled, will the area also double? Explain.

Answer:

A rectangle has side lengths of 5 centimeters and 3 centimeters.

Area of rectangle = 5 Ă— 3 = 15 sq. cm

If the lengths are doubled

l = 2l = 2 Ă— 5 = 10

w = 2w = 2 Ă— 3 = 6

Area of rectangle = 10 Ă— 6 = 60 sq. cm

Question 13.

**Mathematical PRACTICE** Model Math Draw and label two rectangles that each have an area of 24 square inches, but have different perimeters.

Answer:

l = 8 in

w = 3 in

A = 8 Ă— 3 = 24 sq. in

Question 14.

**Building on the Essential Question** How can multiplication and division be used to solve problems involving the area of rectangles?

Answer:

To find the area of a rectangle, multiply the length by the width. The formula is A = L Ă— W where A is the area, L is the length, W is the width, and ‘Ă—’ means multiply.

The division is used to find the unknown length or breadth with the known area of the rectangle.

### McGraw Hill My Math Grade 3 Chapter 13 Lesson 6 My Homework Answer Key

**Practice**

**Find the area of each rectangle.**

Question 1.

_____________ square feet

Answer:

l = 4ft

w = 8 ft

Area of the rectangle = lw

A = 4 Ă— 8

A = 32 sq. ft

Question 2.

_____________ square meters

Answer:

l = 7 m

w = 2 m

Area of the rectangle = lw

A = 7 Ă— 2

A = 14 sq. meters

**Algebra Find the unknown side. Use the area formula.**

Question 3.

36 = l Ă— w

36 = ___________ Ă— 6

The unknown is ___________ inches.

Answer:

36 = l Ă— w

36 = l Ă— 6

l = 36/6

l = 6

The unknown is 6 inches.

Question 4.

24 = l Ă— w

24 = 8 Ă— _____________

The unknown is _____________ meters.

Answer:

Given

24 = l Ă— w

24 = 8 Ă— w

w = 24/8

w = 3

The unknown is 3 meters.

**Vocabulary Check**

Question 5.

Explain how the equation A = l Ă— w is a formula.

Answer:

The formula is a rule using mathematical symbols that can be used to derive consistent results. A formula connect two or more numbers.

A = l x w is a mathematical formula used to determine the area of a rectangle. l represents the length while w represents the width.

**Problem Solving**

For Exercises 6 and 7, use the information below and the rectangle at the right

Mrs. Morris plans to tile her front hallway shown at the right.

Question 6.

If each tile is 1 foot long and 1 foot wide, how many tiles will she need?

Answer:

S = 6ft Ă— 9ft

S = 54 sq. ft

She need 54 tiles.

Question 7.

**Mathematical PRACTICE** Keep Trying Squares of tile come in packages of 6 tiles. How many packages will Mrs. Morris need?

Answer:

S = 6ft Ă— 9ft

S = 54 sq. ft

54/6 = 9 ft

Thus Morris need 9 packages.

**Test Practice**

Question 8.

Which equation can be used to find the area of the rectangle?

(A) 5 + 10 = 15

(B) 10 – 5 = 5

(C) 5 Ă— 10 = 50

(D) 10 Ă· 5 = 2

Answer:

L = 5 cm

W = 10 cm

Area of the rectangle = lw

A = 5 Ă— 10 = 50 sq. cm

So, Option C is correct answer.