Prealgebra 2e — Original English

Simplify and Use Square Roots

Simplify Expressions with Square Roots

To start this section, we need to review some important vocabulary and notation.

Remember that when a number n is multiplied by itself, we can write this as n2, which we read aloud as nsquared.” For example, 82 is read as “8squared.”

We call 64 the square of 8 because 82=64. Similarly, 121 is the square of 11, because 112=121.

Modeling Squares

Do you know why we use the word square? If we construct a square with three tiles on each side, the total number of tiles would be nine.

A square is shown with 3 tiles on each side. There are a total of 9 tiles in the square.

This is why we say that the square of three is nine.

32=9

The number 9 is called a perfect square because it is the square of a whole number.

The chart shows the squares of the counting numbers 1 through 15. You can refer to it to help you identify the perfect squares.

A table with two columns is shown. The first column is labeled “Number” and has the values: n, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15. The second column is labeled “Square” and has the values: n squared, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, and 225.

What happens when you square a negative number?

(−8)2=(−8)(−8)=64

When we multiply two negative numbers, the product is always positive. So, the square of a negative number is always positive.

The chart shows the squares of the negative integers from −1 to −15.

A table is shown with 2 columns. The first column is labeled “Number” and contains the values: n, negative 1, negative 2, negative 3, negative 4, negative 5, negative 6, negative 7, negative 8, negative 9, negative 10, negative 11, negative 12, negative 13, negative 14, and negative 15. The next column is labeled “Square” and contains the values: n squared, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, and 225.

Did you notice that these squares are the same as the squares of the positive numbers?

Square Roots

Sometimes we will need to look at the relationship between numbers and their squares in reverse. Because 102=100, we say 100 is the square of 10. We can also say that 10 is a square root of 100.

Notice (−10)2=100 also, so −10 is also a square root of 100. Therefore, both 10 and −10 are square roots of 100.

So, every positive number has two square roots: one positive and one negative.

What if we only want the positive square root of a positive number? The radical sign, 0, stands for the positive square root. The positive square root is also called the principal square root.

We can also use the radical sign for the square root of zero. Because 02=0,0=0. Notice that zero has only one square root.

The chart shows the square roots of the first 15 perfect square numbers.

A table is shown with 2 columns. The first column contains the values: square root of 1, square root of 4, square root of 9, square root of 16, square root of 25, square root of 36, square root of 49, square root of 64, square root of 81, square root of 100, square root of 121, square root of 144, square root of 169, square root of 196, and square root of 225. The second column contains the values: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15.

Simplify: 25 121.

Solution
Solution
This table illustrates the process of finding the square root of 25, presenting the expression, its result, and the underlying mathematical justification.
25
Since 52=25 5
Demonstrates finding the square root of 121, presenting the mathematical justification and the resulting value.
121
Since 112=121 11

Every positive number has two square roots and the radical sign indicates the positive one. We write 100=10. If we want to find the negative square root of a number, we place a negative in front of the radical sign. For example, 100=−10.

Simplify. 9 144.

Solution
Solution
Simplification of -√9, emphasizing the negative sign's position outside the radical.
9
The negative is in front of the radical sign. 3
This table demonstrates the evaluation of the expression -√144, explaining that the negative sign is applied after calculating the square root.
144
The negative is in front of the radical sign. 12

Square Root of a Negative Number

Can we simplify −25? Is there a number whose square is −25?

()2=−25?

None of the numbers that we have dealt with so far have a square that is −25. Why? Any positive number squared is positive, and any negative number squared is also positive. In the next chapter we will see that all the numbers we work with are called the real numbers. So we say there is no real number equal to −25. If we are asked to find the square root of any negative number, we say that the solution is not a real number.

Simplify: −169 121.

Solution
Solution

There is no real number whose square is −169. Therefore, −169 is not a real number.

The negative is in front of the radical sign, so we find the opposite of the square root of 121.

Demonstrates evaluation of a negative square root, highlighting the sign's placement and showing the final result.
121
The negative is in front of the radical. 11

Square Roots and the Order of Operations

When using the order of operations to simplify an expression that has square roots, we treat the radical sign as a grouping symbol. We simplify any expressions under the radical sign before performing other operations.

Simplify: 25+144 25+144.

Solution
Solution
Step-by-step solution demonstrating the order of operations for evaluating the expression 25 + 144.
Use the order of operations.
25+144
Simplify each radical. 5+12
Add. 17
Step-by-step simplification of a square root expression using the order of operations.
Use the order of operations.
25+144
Add under the radical sign. 169
Simplify. 13

Notice the different answers in parts and of Example 4. It is important to follow the order of operations correctly. In , we took each square root first and then added them. In , we added under the radical sign first and then found the square root.

Estimate Square Roots

So far we have only worked with square roots of perfect squares. The square roots of other numbers are not whole numbers.

A table is shown with 2 columns. The first column is labeled “Number” and contains the values: 4, 5, 6, 7, 8, 9. The second column is labeled “Square root” and contains the values: square root of 4 equals 2, square root of 5, square root of 6, square root of 7, square root of 8, square root of 9 equals 3.

We might conclude that the square roots of numbers between 4 and 9 will be between 2 and 3, and they will not be whole numbers. Based on the pattern in the table above, we could say that 5 is between 2 and 3. Using inequality symbols, we write

2<5<3

Estimate 60 between two consecutive whole numbers.

Solution

Solution

Think of the perfect squares closest to 60. Make a small table of these perfect squares and their squares roots.

A table is shown with 2 columns. The first column is labeled “Number” and contains the values: 36, 49, 64, and 81. There is a balloon coming out of the table between 49 and 64 that says 60. The second column is labeled “Square root” and contains the values: 6, 7, 8, and 9. There is a balloon coming out of the table between 7 and 8 that says square root of 60.
Illustrates bounding a number by consecutive perfect squares and its square root by their respective roots.
Locate 60 between two consecutive perfect squares. 49<60<64
60is between their square roots. 7<60<8

Approximate Square Roots with a Calculator

There are mathematical methods to approximate square roots, but it is much more convenient to use a calculator to find square roots. Find the 0 or x key on your calculator. You will need to use this key to approximate square roots. When you use your calculator to find the square root of a number that is not a perfect square, the answer that you see is not the exact number. It is an approximation, to the number of digits shown on your calculator’s display. The symbol for an approximation is and it is read approximately.

Suppose your calculator has a 10-digit display. Using it to find the square root of 5 will give 2.236067977. This is the approximate square root of 5. When we report the answer, we should use the “approximately equal to” sign instead of an equal sign.

52.236067978

You will seldom use this many digits for applications in algebra. So, if you wanted to round 5 to two decimal places, you would write

52.24

How do we know these values are approximations and not the exact values? Look at what happens when we square them.

2.2360679782=5.0000000022.242=5.0176

The squares are close, but not exactly equal, to 5.

Round 17 to two decimal places using a calculator.

Solution

Solution

Demonstrates the step-by-step calculation and rounding of the square root of 17, showing the initial expression, calculator result, and final approximation.
17
Use the calculator square root key. 4.123105626
Round to two decimal places. 4.12
174.12

Simplify Variable Expressions with Square Roots

Expressions with square root that we have looked at so far have not had any variables. What happens when we have to find a square root of a variable expression?

Consider 9x2, where x0. Can you think of an expression whose square is 9x2?

(?)2=9x2(3x)2=9x2so9x2=3x

When we use a variable in a square root expression, for our work, we will assume that the variable represents a non-negative number. In every example and exercise that follows, each variable in a square root expression is greater than or equal to zero.

Simplify: x2.

Solution

Solution

Think about what we would have to square to get x2. Algebraically, (?)2=x2

Illustrates the algebraic simplification of `sqrt(x^2)` to `x`, based on the property `(x)^2=x^2`.
x2
Since (x)2=x2 x

Simplify: 16x2.

Solution

Solution

Illustrates the simplification of the square root of 16x squared, showing the original expression, reasoning, and final simplified form.
16x2
Since(4x)2=16x2 4x

Simplify: 81y2.

Solution

Solution

This table illustrates the simplification of the mathematical expression -sqrt(81y^2) to -9y, including the reasoning.
81y2
Since(9y)2=81y2 9y

Simplify: 36x2y2.

Solution

Solution

Illustrates the simplification of a square root expression along with its underlying reason.
36x2y2
Since(6xy)2=36x2y2 6xy

Use Square Roots in Applications

As you progress through your college courses, you’ll encounter several applications of square roots. Once again, if we use our strategy for applications, it will give us a plan for finding the answer!

Square Roots and Area

We have solved applications with area before. If we were given the length of the sides of a square, we could find its area by squaring the length of its sides. Now we can find the length of the sides of a square if we are given the area, by finding the square root of the area.

If the area of the square is A square units, the length of a side is A units. See Table 14.

Area (square units) Length of side (units)
9 9=3
144 144=12
A A

Mike and Lychelle want to make a square patio. They have enough concrete for an area of 200 square feet. To the nearest tenth of a foot, how long can a side of their square patio be?

Solution
Solution

We know the area of the square is 200 square feet and want to find the length of the side. If the area of the square is A square units, the length of a side is A units.

Step-by-step guide demonstrating how to calculate the side length of a square patio from its area, using square roots and rounding to one decimal place.
What are you asked to find? The length of each side of a square patio
Write a phrase. The length of a side
Translate to an expression. A
Evaluate A when A=200. 200
Use your calculator. 14.142135...
Round to one decimal place. 14.1 feet
Write a sentence. Each side of the patio should be 14.1 feet.

Square Roots and Gravity

Another application of square roots involves gravity. On Earth, if an object is dropped from a height of h feet, the time in seconds it will take to reach the ground is found by evaluating the expression h4. For example, if an object is dropped from a height of 64 feet, we can find the time it takes to reach the ground by evaluating 644.

Steps to simplify the mathematical expression sqrt(64)/4.
644
Take the square root of 64. 84
Simplify the fraction. 2

It would take 2 seconds for an object dropped from a height of 64 feet to reach the ground.

Christy dropped her sunglasses from a bridge 400 feet above a river. How many seconds does it take for the sunglasses to reach the river?

Solution
Solution
This table outlines the step-by-step solution to a problem involving calculating the time for sunglasses to fall into a river, from problem statement to final numerical answer.
What are you asked to find? The number of seconds it takes for the sunglasses to reach the river
Write a phrase. The time it will take to reach the river
Translate to an expression. h4
Evaluate h4 when h=400. 4004
Find the square root of 400. 204
Simplify. 5
Write a sentence. It will take 5 seconds for the sunglasses to reach the river.

Square Roots and Accident Investigations

Police officers investigating car accidents measure the length of the skid marks on the pavement. Then they use square roots to determine the speed, in miles per hour, a car was going before applying the brakes. According to some formulas, if the length of the skid marks is d feet, then the speed of the car can be found by evaluating 24d.

After a car accident, the skid marks for one car measured 190 feet. To the nearest tenth, what was the speed of the car (in mph) before the brakes were applied?

Solution
Solution
This table outlines the step-by-step process of calculating a car's speed using a square root formula and a given distance, resulting in a numerical approximation.
What are you asked to find? The speed of the car before the brakes were applied
Write a phrase. The speed of the car
Translate to an expression. 24d
Evaluate24dwhend=190. 24·190
Multiply. 4,560
Use your calculator. 67.527772...
Round to tenths. 67.5
Write a sentence. The speed of the car was approximately 67.5 miles per hour.

Key Concepts

  • Square Root Notation m is read ‘the square root of m
    If m=n2, then m=n, for n0. This image labels the parts of a radical: the radical sign (square root symbol) and the radicand (the number or expression 'm' inside it).
  • Use a strategy for applications with square roots.
    • Identify what you are asked to find.
    • Write a phrase that gives the information to find it.
    • Translate the phrase to an expression.
    • Simplify the expression.
    • Write a complete sentence that answers the question.

Section Exercises

Practice Makes Perfect

Simplify Expressions with Square Roots

In the following exercises, simplify.

36

Solution

6

4

64

Solution

8

144

4

Solution

−2

100

1

Solution

−1

121

−121

Solution

not a real number

−36

−9

Solution

not a real number

−49

9+16

Solution

5

25+144

9+16

Solution

7

25+144

Estimate Square Roots

In the following exercises, estimate each square root between two consecutive whole numbers.

70

Solution

8<70<9

55

200

Solution

14<200<15

172

Approximate Square Roots with a Calculator

In the following exercises, use a calculator to approximate each square root and round to two decimal places.

19

Solution

4.36

21

53

Solution

7.28

47

Simplify Variable Expressions with Square Roots

In the following exercises, simplify. (Assume all variables are greater than or equal to zero.)

y2

Solution

y

b2

49x2

Solution

7x

100y2

64a2

Solution

−8a

25x2

144x2y2

Solution

12xy

196a2b2

Use Square Roots in Applications

In the following exercises, solve. Round to one decimal place.

Landscaping Reed wants to have a square garden plot in his backyard. He has enough compost to cover an area of 75 square feet. How long can a side of his garden be?

Solution

8.7 feet

Landscaping Vince wants to make a square patio in his yard. He has enough concrete to pave an area of 130 square feet. How long can a side of his patio be?

Gravity An airplane dropped a flare from a height of 1,024 feet above a lake. How many seconds did it take for the flare to reach the water?

Solution

8 seconds

Gravity A hang glider dropped his cell phone from a height of 350 feet. How many seconds did it take for the cell phone to reach the ground?

Gravity A construction worker dropped a hammer while building the Grand Canyon skywalk, 4,000 feet above the Colorado River. How many seconds did it take for the hammer to reach the river?

Solution

15.8 seconds

Accident investigation The skid marks from a car involved in an accident measured 54 feet. What was the speed of the car before the brakes were applied?


Accident investigation The skid marks from a car involved in an accident measured 216 feet. What was the speed of the car before the brakes were applied?

Solution

72 mph

Accident investigation An accident investigator measured the skid marks of one of the vehicles involved in an accident. The length of the skid marks was 175 feet. What was the speed of the vehicle before the brakes were applied?

Accident investigation An accident investigator measured the skid marks of one of the vehicles involved in an accident. The length of the skid marks was 117 feet. What was the speed of the vehicle before the brakes were applied?

Solution

53.0 mph

Everyday Math

Decorating Denise wants to install a square accent of designer tiles in her new shower. She can afford to buy 625 square centimeters of the designer tiles. How long can a side of the accent be?

Decorating Morris wants to have a square mosaic inlaid in his new patio. His budget allows for 2,025 tiles. Each tile is square with an area of one square inch. How long can a side of the mosaic be?

Solution

45 inches

Writing Exercises

Why is there no real number equal to −64?

What is the difference between 92 and 9?

Solution

Answers will vary. 92 reads: “nine squared” and means nine times itself. The expression 9 reads: “the square root of nine” which gives us the number such that if it were multiplied by itself would give you the number inside of the square root.

Self Check

After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

A self-assessment table for square root skills, with columns for 'Confidently,' 'With some help,' and 'No-I don't get it!' for topics like simplifying, estimating, approximating, and applications.

Overall, after looking at the checklist, do you think you are well-prepared for the next Chapter? Why or why not?

Chapter Review Exercises

Decimals

Name Decimals

In the following exercises, name each decimal.

0.8

0.375

Solution

three hundred seventy-five thousandths

0.007

5.24

Solution

five and twenty-four hundredths

−12.5632

−4.09

Solution

negative four and nine hundredths

Write Decimals

In the following exercises, write as a decimal.

three tenths

nine hundredths

Solution

0.09

twenty-seven hundredths

ten and thirty-five thousandths

Solution

10.035

negative twenty and three tenths

negative five hundredths

Solution

−0.05

Convert Decimals to Fractions or Mixed Numbers

In the following exercises, convert each decimal to a fraction. Simplify the answer if possible.

0.43

0.825

Solution

3340

9.7

3.64

Solution

31625

Locate Decimals on the Number Line

0.6

−0.9

2.2

−1.3

Order Decimals

In the following exercises, order each of the following pairs of numbers, using < or >.

0.6___0.8

Solution

<

0.2___0.15

0.803____0.83

Solution

<

−0.56____−0.562

Round Decimals

In the following exercises, round each number to the nearest: hundredth tenth whole number.

12.529

Solution
  1. 12.53
  2. 12.5
  3. 13

4.8447

5.897

Solution
  1. 5.90
  2. 5.9
  3. 6

Decimal Operations

Add and Subtract Decimals

In the following exercises, add or subtract.

5.75+8.46

32.898.22

Solution

24.67

2419.31

10.2+14.631

Solution

24.831

−6.4+(−2.9)

1.834.2

Solution

−2.37

Multiply Decimals

In the following exercises, multiply.

(0.3)(0.7)

(−6.4)(0.25)

Solution

−1.6

(−3.35)(−12.7)

(15.4)(1000)

Solution

15,400

Divide Decimals

In the following exercises, divide.

0.48÷6

4.32÷24

Solution

0.18

$6.29÷12

(−0.8)÷(−0.2)

Solution

4

1.65÷0.15

9÷0.045

Solution

200

Use Decimals in Money Applications

In the following exercises, use the strategy for applications to solve.

Miranda got $40 from her ATM. She spent $9.32 on lunch and $16.99 on a book. How much money did she have left? Round to the nearest cent if necessary.

Jessie put 8 gallons of gas in her car. One gallon of gas costs $3.528. How much did Jessie owe for all the gas?

Solution

$28.22

A pack of 16 water bottles cost $6.72. How much did each bottle cost?

Alice bought a roll of paper towels that cost $2.49. She had a coupon for $0.35 off, and the store doubled the coupon. How much did Alice pay for the paper towels?

Solution

$1.79

Decimals and Fractions

Convert Fractions to Decimals

In the following exercises, convert each fraction to a decimal.

35

78

Solution

0.875

1920

214

Solution

−5.25

13

611

Solution

0.54

Order Decimals and Fractions

In the following exercises, order each pair of numbers, using < or >.

12___0.2

35___0.

Solution

>

78___−0.84

512___−0.42

Solution

>

0.625___1320

0.33___516

Solution

>

In the following exercises, write each set of numbers in order from least to greatest.

23,1720,0.65

79,0.75,1115

Solution

1115,0.75,79

Simplify Expressions Using the Order of Operations

In the following exercises, simplify

4(10.35.8)

34(15.447.4)

Solution

6.03

30÷(0.45+0.15)

1.6+38

Solution

1.975

52(0.5)+(0.4)2

25·910+0.14

Solution

−0.22

Find the Circumference and Area of Circles

In the following exercises, approximate the circumference and area of each circle.

radius=6 in.

radius=3.5 ft.

Solution
  1. 21.98 ft.
  2. 38.465 sq.ft.

radius=733m

diameter=11 cm

Solution
  1. 34.54 cm
  2. 94.985 sq.cm

Solve Equations with Decimals

Determine Whether a Decimal is a Solution of an Equation

In the following exercises, determine whether the each number is a solution of the given equation.

x0.4=2.1
x=1.7 x=2.5

y+3.2=−1.5
y=1.7 y=−4.7

Solution
  1. no
  2. yes

u2.5=−12.5
u=−5 u=−31.25

0.45v=−40.5
v=−18.225 v=−90

Solution
  1. no
  2. yes

Solve Equations with Decimals

In the following exercises, solve.

m+3.8=7.5

h+5.91=2.4

Solution

h = −3.51

a+2.26=−1.1

p4.3=−1.65

Solution

p = 2.65

x0.24=−8.6

j7.42=−3.7

Solution

j = 3.72

0.6p=13.2

−8.6x=34.4

Solution

x = −4

−22.32=−2.4z

a0.3=−24

Solution

a = −7.2

p−7=−4.2

s−2.5=−10

Solution

s = 25

Translate to an Equation and Solve

In the following exercises, translate and solve.

The difference of n and 15.2 is 4.4.

The product of −5.9 and x is −3.54.

Solution

−5.9x = −3.54; x = 0.6

The quotient of y and −1.8 is −9.

The sum of m and (−4.03) is 6.8.

Solution

m + (−4.03) = 6.8; m = 10.83

Averages and Probability

Find the Mean of a Set of Numbers

In the following exercises, find the mean of the numbers.

2,4,1,0,1,and1

$270, $310.50, $243.75, and $252.15

Solution

$269.10

Each workday last week, Yoshie kept track of the number of minutes she had to wait for the bus. She waited 3,0,8,1,and8 minutes. Find the mean.

In the last three months, Raul’s water bills were $31.45,$48.76,and$42.60. Find the mean.

Solution

$40.94

Find the Median of a Set of Numbers

In the following exercises, find the median.

41, 45, 32, 60, 58

25, 23, 24, 26, 29, 19, 18, 32

Solution

24.5

The ages of the eight men in Jerry’s model train club are 52,63,45,51,55,75,60,and59. Find the median age.

The number of clients at Miranda’s beauty salon each weekday last week were 18,7,12,16,and20. Find the median number of clients.

Solution

16 clients

Find the Mode of a Set of Numbers

In the following exercises, identify the mode of the numbers.

6, 4, 4,5, 6,6, 4, 4, 4, 3, 5

The number of siblings of a group of students: 2, 0, 3, 2, 4, 1, 6, 5, 4, 1, 2, 3

Solution

2

Use the Basic Definition of Probability

In the following exercises, solve. (Round decimals to three places.)

The Sustainability Club sells 200 tickets to a raffle, and Albert buys one ticket. One ticket will be selected at random to win the grand prize. Find the probability Albert will win the grand prize. Express your answer as a fraction and as a decimal.

Luc has to read 3 novels and 12 short stories for his literature class. The professor will choose one reading at random for the final exam. Find the probability that the professor will choose a novel for the final exam. Express your answer as a fraction and as a decimal.

Solution

15;0.2

Ratios and Rate

Write a Ratio as a Fraction

In the following exercises, write each ratio as a fraction. Simplify the answer if possible.

28 to 40

56 to 32

Solution

74

3.5 to 0.5

1.2 to 1.8

Solution

23

134to158

213to514

Solution

49

64 ounces to 30 ounces

28 inches to 3 feet

Solution

79

Write a Rate as a Fraction

In the following exercises, write each rate as a fraction. Simplify the answer if possible.

180 calories per 8 ounces

90 pounds per 7.5 square inches

Solution

12pounds1square inch

126 miles in 4 hours

$612.50 for 35 hours

Solution

$352hours

Find Unit Rates

In the following exercises, find the unit rate.

180 calories per 8 ounces

90 pounds per 7.5 square inches

Solution

12 pounds/sq.in.

126 miles in 4 hours

$612.50 for 35 hours

Solution

$17.50/hour

Find Unit Price

In the following exercises, find the unit price.

t-shirts: 3 for $8.97

Highlighters: 6 for $2.52

Solution

$0.42

An office supply store sells a box of pens for $11. The box contains 12 pens. How much does each pen cost?

Anna bought a pack of 8 kitchen towels for $13.20. How much did each towel cost? Round to the nearest cent if necessary.

Solution

$1.65

In the following exercises, find each unit price and then determine the better buy.

Shampoo: 12 ounces for $4.29 or 22 ounces for $7.29?

Vitamins: 60 tablets for $6.49 or 100 for $11.99?

Solution

$0.11, $0.12; 60 tablets for $6.49

Translate Phrases to Expressions with Fractions

In the following exercises, translate the English phrase into an algebraic expression.

535 miles per hhours

a adults to 45 children

Solution

aadults45children

the ratio of 4y and the difference of x and 10

the ratio of 19 and the sum of 3 and n

Solution

193+n

Simplify and Use Square Roots

Simplify Expressions with Square Roots

In the following exercises, simplify.

64

144

Solution

12

25

81

Solution

−9

−9

−36

Solution

not a real number

64+225

64+225

Solution

17

Estimate Square Roots

In the following exercises, estimate each square root between two consecutive whole numbers.

28

155

Solution

12<155<13

Approximate Square Roots

In the following exercises, approximate each square root and round to two decimal places.

15

57

Solution

7.55

Simplify Variable Expressions with Square Roots

In the following exercises, simplify. (Assume all variables are greater than or equal to zero.)

q2

64b2

Solution

8b

121a2

225m2n2

Solution

15mn

100q2

49y2

Solution

7y

4a2b2

121c2d2

Solution

11cd

Use Square Roots in Applications

In the following exercises, solve. Round to one decimal place.

Art Diego has 225 square inch tiles. He wants to use them to make a square mosaic. How long can each side of the mosaic be?

Landscaping Janet wants to plant a square flower garden in her yard. She has enough topsoil to cover an area of 30 square feet. How long can a side of the flower garden be?

Solution

5.5 feet

Gravity A hiker dropped a granola bar from a lookout spot 576 feet above a valley. How long did it take the granola bar to reach the valley floor?

Accident investigation The skid marks of a car involved in an accident were 216 feet. How fast had the car been going before applying the brakes?

Solution

72 mph

Chapter Practice Test

Write six and thirty-four thousandths as a decimal.

Write 1.73 as a fraction.

Solution

173100

Write 58 as a decimal.

Round 16.749 to the nearest tenth hundredth whole number

Solution
  1. 16.7
  2. 16.75
  3. 17

Write the numbers 45,−0.1,0.804,29,−7.4,0.21 in order from smallest to largest.

In the following exercises, simplify each expression.

15.4+3.02

Solution

18.42

205.71

(0.64)(0.3)

Solution

0.192

(−4.2)(100)

0.96÷(−12)

Solution

−0.08

−5÷0.025

−0.6÷(−0.3)

Solution

2

(0.7)2

24÷(0.1+0.02)

Solution

200

4(10.35.8)

1.6+38

Solution

1.975

23(14.654.6)

In the following exercises, solve.

m+3.7=2.5

Solution

−1.2

h0.5=4.38

−6.5y=−57.2

Solution

8.8

1.94=a2.6

Three friends went out to dinner and agreed to split the bill evenly. The bill was $79.35. How much should each person pay?

Solution

$26.45

A circle has radius 12. Find the circumference and area. [Use3.14forπ.]

The ages, in months, of 10 children in a preschool class are:
55, 55, 50, 51, 52, 50, 53, 51, 55, 49
Find the mean median mode

Solution
  1. 52.1
  2. 51.5
  3. 55

Of the 16 nurses in Doreen’s department, 12 are women and 4 are men. One of the nurses will be assigned at random to work an extra shift next week. Find the probability a woman nurse will be assigned the extra shift. Convert the fraction to a decimal.

Find each unit price and then the better buy.
Laundry detergent: 64 ounces for $10.99 or 48 ounces for $8.49

Solution

The unit prices are $0.172 per ounce for 64 ounces, and $0.177 per ounce for 48 ounces; 64 ounces is the better buy.

In the following exercises, simplify.

36+64

144n2

Solution

12n

Estimate 54 to between two whole numbers.

Yanet wants a square patio in her backyard. She has 225 square feet of tile. How long can a side of the patio be?

Solution

15 feet