All the solutions provided in McGraw Hill My Math Grade 4 Answer Key PDF Chapter 13 Lesson 1 Measure Perimeter will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 4 Answer Key Chapter 13 Lesson 1 Measure Perimeter
The distance around a closed figure is called a perimeter.
Math in My World
Example 1
Berto walked around a park on the rectangular path shown. How far did Berto walk?
Opposite sides of a rectangle are equal. So, the side lengths are 12 yards, 12 yards, 6 yards, and 6 yards.
Add the measures of all of the sides of the figure.
Perimeter = 12 yards + 12 yards + 6 yards + 6 yards
Perimeter = ______________ yards
So, Berto walked ______________ yards.
Answer: The perimeter is 36 yards.
So, Berto walked 36 yards.
Explanation: Given that, the length is 6 yd and the width is 12 yd.
Now, we will find the perimeter of a rectangular park path.
The formula for the perimeter of a rectangle is, 2(l+w)
Perimeter = 2(6+12) = 2(18)
So, the perimeter of the rectangular path is 36 yards.
Therefore, Betro walked 36 yards.
Example 2
Find the perimeter of a square with side lengths of 6 inches.
One Way:
Add the measures of all of the sides of the figure.
The sides of a square are 6 inches.
P = 6 inches + 6 inches + 6 inches + 6 inches
P = 24 inches
Another Way:
Use a formula.
Multiply the length of one side by 4 because there are 4 sides of equal length.
P = 4 × s ← s is equal to one side length
P = 4 × 6 inches
P = 24 inches
So, the perimeter of the square is ___________ inches.
Answer: So, the perimeter of the square is 24 inches.
Talk Math
Describe two ways to find the perimeter of a square.
Answer:
One Way:
Add the measures of all of the sides of the figure.
P = a+a+a+a.
Another Way:
Use a formula.
Multiply the length of one side by 4 because there are 4 sides of equal length.
P = 4 × s ← s is equal to one side length
P = 4a
So, the perimeter of the square is 4a.
Guided Practice
Find each perimeter.
Question 1.
P = _____________
Answer: 36 cm
Explanation: Given a square, one side of the square is 8 cm.
Square has equal sides.
The perimeter of a square is, 4a or 4*s
P = 4 x 8
P = 36 cm.
Question 2.
P = _____________
Answer: 22 in
Explanation: Given the length is 7 inches and the width is 4 inches.
Now, we will find the perimeter of a rectangle.
The perimeter of a Rectangle is, 2(l+w)
P = 2(4+7)
P = 2(11)
P = 22 in.
McGraw Hill My Math Grade 4 Chapter 13 Lesson 1 My Homework Answer Key
Practice
Find each perimeter.
Question 1.
P = ____________ cm
Answer: 16 cm
Explanation: Given that, the length is 5cm and the width is 3 cm.
Now, find the perimeter of a rectangle.
The formula perimeter of a rectangle is, 2(l+w)
P = 2(5+3) = 2(8)
P = 16 cm.
Question 2.
P = ______________ yd
Answer: 32 yd
Explanation: Given that, the length is 12 yd and the width is 4 yd.
we will find the perimeter of a rectangle.
The formula for the perimeter of a rectangle is, 2(l+w)
P = 2(12+4) = 2(16)
P = 32 yd
Question 3.
P = _____________ mm
Answer: 28mm
Explanation: Given that, the side is 7mm.
Now, we will find the perimeter of a square.
The formula for the perimeter of a square is, 4(s)
P = 4(7) = 28
P = 28 mm.
Question 4.
P = _____________ ft
Answer: 24 ft
Explanation: Given that, the length is 1 ft and the width is 11ft.
The formula for the perimeter of a rectangle is, 2(l+w)
P = 2(1+11) = 2(12)
P = 24 ft.
Find the perimeter of each rectangle in units.
Question 5.
P = _____________ units
Answer: 24 units
Explanation: The given figure consists of,
The number of rows is 7.
The number of columns is 5.
The formula for the perimeter of a rectangle is, 2(l+w)
P = 2(7+5) = 2(12)
P = 24 units.
Question 6.
P = _____________ units
Answer: 12 units.
Explanation: Given figure consists of,
The number of rows is 3.
The number of columns i2 3.
The formula for the perimeter of a square is, 4s
P = 4*3= 12
P = 12 units.
Problem Solving
Question 7.
Mathematical PRACTICE Model Math Justin walked his dog 2 blocks west, 6 blocks north, 2 blocks east, and 6 blocks south. Then he walked his other dog along the same route. Draw a picture to represent Justin’s route. How many blocks did Justin walk in all?
Answer: The picture to represent Justin’s route is,
Given that,
Justin walked his dog for 16 blocks.
Justin walked with another dog 16 blocks.
So, the total number of blocks Justin walked is, 16 + 16 = 32
Therefore, Justin walks in all 32 blocks.
Question 8.
A rectangle has a perimeter of 30 inches. One side measures 5 inches. What are the measures of the other three sides?
Answer: The measures of the other three sides are 5, 10, and 10 inches.
Explanation: Given, that the perimeter of a rectangle is 30 inches.
One side measure is 5 inches.
In rectangle opposite sides are equal. So, the other side is also 5 inches.
The length is 10 because, 10 + 5 = 15.
The perimeter of a rectangle is, 2(l+w)
P= 2(10+5) = 2(15) = 30 inches.
We get the given perimeter value.
So, the three sides are 5, 10, and 10.
Question 9.
Carolla is putting a border around the edge of a rectangular bulletin board. One side of the bulletin board measures 2 feet and another side measures 4 feet. Are 10 feet of border enough? Explain.
Answer: Given that, one side of the bulletin board is 2 ft and the other side is 4 ft.
Now, we will find the perimeter of a rectangular bulletin board.
The perimeter of a rectangular bulletin board is, 2(l+w)
P= 2(2+4)
P = 2(6)
P =12 ft.
So, 10 is not enough. Because the perimeter of the bulletin board is 12 ft.
Vocabulary Check
Question 10.
Write a definition for the term perimeter.
Answer: The term perimeter is defined as the total length of its boundary. It is determined by adding the length of all the sides and edges enclosing the shape.
Test Practice
Question 11.
What is the measure of the unknown side of the rectangle?
(A) 23 meters
(B) 14 meters
(C) 7 meters
(D) 5 meters
Answer: C
Explanation: Given that the perimeter is 32m and one side is 9m.
Now, we will find the other side value.
Based on the given option another side is 7m.
The formula for the perimeter of a rectangle is 2(l+w)
P = 2(9+7) = 2(16) = 32m
We get the given perimeter value. So option C is correct.