Answer Key

Chapter 1 Numbers and Operations

Exercise 1

1. 10 is a natural number, a whole number, an integer, a rational number, and a real number.

2. −7.3 is a rational number and a real number.

3. −74 is an integer, a rational number, and a real number.

4. −1,000 is an integer, a rational number, and a real number.

5. 0.555 ... is a rational number and a real number.

6. Images is a rational number and a real number.

7. Images is a rational number and a real number.

8. 0 is a whole number, an integer, a rational number, and a real number.

9. Images is an irrational number and a real number.

10. Undefined

11. 0

12. Undefined

13. Distributive property

14. Zero factor property

15. Associative property of multiplication

Chapter 2 Integers

Exercise 2

1. |−45| = 45

2. |58| = 58

3. |−5| = 5

4. “Negative nine plus the opposite of negative four equals negative nine plus four.”

5. “Negative nine minus negative four equals negative nine plus four.”

6. −80 + −40 = −120

7. Images

8. (−100)(−8) = 800

9. Images

10. −458 + 0 = −458

11. 4(−3)(0)(999)(−500) = 0

12. Images

13. Images

14. Images

15. Images

16. (−3)(1)(−1)(−5)(−2)(2)(−10) = −600

17. (−3)(1)(−1)(−5)(−2)(0)(−10) = 0

18.

Images

19.

Images

20.

Images

Chapter 3 Exponents

Exercise 3

1. “six to the fifth”

2. “negative five to the fourth”

3. “four to the zero”

4. “negative nine squared”

5. (−4)(−4)(−4)(−4)(−4) = (−4)5

6. 8 × 8 × 8 × 8 × 8 × 8 × 8 = 87

7. 28 = 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 256

8. 54 = 5 × 5 × 5 × 5 = 625

9. (−4)5 = (−4)(−4)(−4)(−4)(−4) = −1,024

10. 09 = 0

11. (−2) = 1

12. 0−4 is the notation for Images or Images, which is undefined.

13. Images

14. Images

15. Images

Chapter 4 Order of Operations

Exercise 4

1. Images

2. Images

3. Images

4. Images

5. Images

6. Images

7. Images

8. Images

9. Images

10. Images

11. Images

Chapter 5 Fractions

Exercise 5

1. Images

2. Images

3. Images

4. Images

5. Images

6. Images

7. Images

8. Images

9. Images

10. Images

11. Images

12. Images

Chapter 6 Decimals

Exercise 6

1. Images

2. Images

3. Prediction: Five places

Images

4. Prediction: Six places

Images

5.

Images

Answer: 11.05 (using a calculator)

6. Images

Answer: 8.1 (using a calculator)

7. Divide 2.917 by 0.37 and round to three places

Images

Answer: 7.884 (using a calculator)

8. Multiply 6.678 by 0.37 and round to two places

Answer: 2.47 (using a calculator)

9. Divide 3.977 by 0.0372 and round to three places

Images

Answer: 106.909 (using a calculator)

10. Multiply 45.67892 by 0.0374583 and round to four places

Answer: 1.7111 (using a calculator)

Chapter 7 Percents

Exercise 7

1. Images

2. Images

3. Images

4. Images

5. Images

6. Images

7. Images

8. Images

9. Images

10. Images

11. Images

12. Images

13. Images

14. Images

15. Images

Chapter 8 Units of Measurement

Exercise 8

1. Images

2. Images

3. Images

4. Images

5. Images

6. Images

7. Images

8. Images

9. Images

10. Images

11. Images

12. Images

13. Images

14. Images

15. Compare: Images to Images.

The better buy is 9 oz for $4.99.

16. 250 m ÷ 103 (three moves left) = 250 m ÷ 1,000 = 0.25 km

17. Images

The package weighs 60 oz.

18. Images

19. Images

20. Images

21. The thermometer is reading four tick marks above 10°. Since each interval between tick marks represents 1°, the thermometer is reading 4° above 10°, which is 14°C.

Chapter 9 Ratios and Proportions

Exercise 9

1. Images because both are in the same units

2. Images

3. Images

4. Images

5. Images

6. Images

7. Let w = the number

Images

8. Let p = the part

Images

9. You will earn only one-half of a year’s interest.

Let A = the amount you will earn. Then Images is the amount of interest you will earn in 6 months.

10. Images

11. Images

12. Images

13. Images

14. Images

Chapter 10 Roots and Radicals

Exercise 10

1. 12 × 12 = 144 and −12 × −12 = 144

Thus, 12 and −12 are the two square roots of 144.

2. Images and Images

Thus, Images and Images are the two square roots of Images.

3. 0.8 × 0.8 = 0.64 and −0.8 ×−0.8 = 0.64

Thus, 0.8 and −0.8 are the two square roots of 0.64.

4. 20 × 20 = 400 and −20 × −20 = 400

Thus, 20 and −20 are the two square roots of 400.

5. 6 × 6 = 36, so 6 is the positive square root of 36.

Thus, Images.

6. −9 is a negative number; square roots of negative numbers are not real numbers.

Thus, Images is undefined for the set of real numbers.

7. Images, so Images is the positive square root of Images.

Thus, Images

8. Images

13 × 13 = 169, so 13 is the positive square root of 169.

Thus, Images.

9. −2 × −2 × −2 = −8

Thus, Images.

10. Images

Thus, Images

Chapter 11 Algebraic Expressions

Exercise 11

1. The variable is s, and the constant is 4.

2. The numerical coefficient is −12.

3. The numerical coefficient is 1.

4. The numerical coefficient is Images.

5. −5x = −5(9) = −45

6. 2xyz = 2(9)(−2)(−3) = 108

7. Images

8. Images

9. Images

10. Images

11. Images

12. Images

13. Images

14. 12 + (x2 + y) = 12 + x2 + y

15. 8 − (2x − 4y) = 8 − 2x + 4y

Chapter 12 Formulas

Exercise 12

1. Images

2. P = 4s = 4(10 m) = 40 m

3. Images

4. A = 15 ft × 6 ft = 90 ft2

5. Images

6. A = πr2 ≈ (3.14)(5 yd)2 = (3.14)(25 yd2) = 78.5 yd2

7. V = πr2h = (3.14)(10 ft)2 (30 ft) = (3.14)(l00 ft2)(30 ft) = 9,420 ft3

8. Images

9. Images

10. Images

Chapter 13 Polynomials

Exercise 13

1. x2x + 1 is a trinomial.

2. 125x3 − 64y3 is a binomial.

3. 2x2 + 7x − 4 is a trinomial.

4. Images is a monomial.

5. 2x4 + 3x3 − 7x2x + 8 is a polynomial.

6. −15x + 17x = 2x

7. 14xy3 − 7x3y2 is simplifed.

8. 10x2 − 2x2 − 20x2 = −12x2

9. 10 + 10x is simplifed.

10. Images

11. 12x3 − 5x2 + 10x − 60 + 3x3 − 7x2 − 1 = 15x3 − 12x2 + 10x − 61

12. Images

13. Images

14. Images

15. Images

Chapter 14 Solving Equations

Exercise 14

1. Images

2. Images

3. Images

4. Images

5. Two more than three times a number x = four less than six times the number x.

Images

6. Images

7. Images

8. Images

9. Images

The student’s percent grade is 87.5%.

10. Images

The regular price of the shirt is $95.

Chapter 15 Informal Geometry

Exercise 15

1. Yes, the size and shape appear to be the same.

2. No, the size is about the same but the shape is different.

3. No, the size is different.

4. Yes, the shape is the same.

5. Yes, the shape is the same.

6. No, the shape is different.

7.

Images

Dashed lines are lines of symmetry.

8. The figure does not have line symmetry.

9. Acute, because 50° is between 0° and 90°

10. Right, because the angle is exactly 90°

11. Obtuse, because 130° is between 0° and 180°

12. Intersecting

13. Parallel

14. Hexagon, because it has exactly six sides

15. Heptagon, because it has exactly seven sides

16. Isosceles, because it has two congruent sides

17. Equilateral, because it has three congruent sides

18. Acute triangle, because it has three acute angles

19. Obtuse triangle, because it has one obtuse angle

20. Right triangle, because it has one right angle

21. Parallelogram, because opposite sides are congruent and parallel

22. Rectangle, because it is a parallelogram that has four right angles

23. Trapezoid, because it has exactly one pair of parallel sides

24. The length of the diameter is 2 × 5.4 yd = 10.8 yd.

25. Rectangular prism, because it has two parallel and congruent rectangular bases and rectangles for sides

26. Cylinder, because it has two parallel congruent bases, which are circles, and it has one rectangular side that wraps around

27. A square or rectangular pyramid, because it is a solid with exactly one base, triangular sides, and a square base

28. Sphere, because it is a three-dimensional solid that is shaped like a ball

29. Triangular pyramid, because it is a solid with exactly one base, triangular sides, and a triangular base

30. Pentagonal prism, because it has two parallel and congruent pentagonal bases and rectangles for sides

Chapter 16 Perimeter, Area, and Volume

Exercise 16

1. Images

2. The area of the floor is 20 ft × 30 ft = 600 ft2. Because the tiles are each of size 12 in × 12 in = 1 ft × 1 ft = 1 ft2, 600 tiles are needed.

3.

Images

The size of the complete region is (12 ft + 1 ft + 1 ft) = 14 ft by (10 ft + 1 ft + 1 ft) = 12 ft, so the area A = 14 ft × 12 ft = 168 ft2.

4. The area of the rectangle is Ar = 4 ft × 9 ft = 36 ft2. Because the square has the same area, the side of the square is Images.

5.

Images

The perimeter P = 2 × 30 ft + 2 × 21 ft = 102 ft. Dividing 102 ft by 3 ft between each post gives 34. Thus, 34 posts are needed.

6. A = πr2 ≈ 3.14(10 ft)2 = 3.14(100 ft2) = 314 ft2

7. Images

8. a. Images

b. The number of bushels is Images

c. The value of the wheat in the full silo is Images

9. Images

10. Images cubic units

11. Find the surface area of the box.

Images

Sum the areas of the faces.

S.A. = 2(8 ft)(30 ft) + 2(20 ft)(30 ft) + 2(8 ft)(20 ft) = 2,000 ft2

Chapter 17 Pythagorean Theorem

Exercise 17

1. Images

2. Images

3. Images

4. Images

5. Images

The triangle is not a right triangle.

6. The required area is the area of the semicircle minus the area of the triangle. Let A be the area of the semicircle and let T be the area of the triangle. Then, to find the area of the semicircle, the radius length must be known. The diameter and thus the radius can be found by using the Pythagorean theorem on the right triangle. Let d be the length of the diameter.

Images

Images

The radius is Images

Images

The required area is Images

7. Images

d2 = 32 + 42 = 25

d = 5

(The triangle in this figure is the special 3-4-5 triangle. Any triangle similar to this triangle has proportional side lengths, such as the 27-36-45 triangle of problem 1 earlier.)

8. The length of the sides of the square is needed for the perimeter. You can use the Pythagorean theorem to find the side length. Let s be the side length and let P be the perimeter. 32

s2 + s2 = 32

2s2 = 32

s2 = 16

s = 4

P = 4s = 4 × 4 = 16 units

9. Because 4 is the largest number, the question is

Images

The triangle is a right triangle.

10. Images

Images

The ladder will reach up on the wall approximately 3.92 m.

Chapter 18 Counting and Probability

Exercise 18

1. no. of ways to select one door and one curtain = (no. of ways to select a door) × (no. of ways to select a curtain) = 3 × 4 = 12 different ways

2. no. of codes possible = (no. of ways to select first letter) × (no. of ways to select second letter) × (no. of ways to select third letter) = 15 × 15 × 15 = 3,375 different codes

3. no. of ways to select one bread, one sandwich filling, one bag of chips, and one drink = (no. of ways to select a bread) × (no. of ways to select a sandwich filling) × (no. of ways to select a bag of chips) × (no. of ways to select a drink) = 3 × 4 × 2 × 3 = 72 different lunches

4. Images

5. Images

6. Images

7. Images

8. Images

9. The events are independent, so Images

10. The events are independent, so Images

Chapter 19 Mean, Median, Mode, and Range

Exercise 19

1. Images

2. Images

3. Images

4. Images

5. Images

6. median = 30

7. Images

8. Images

9. median = 3

10. median = 4

11. no mode

12. mode is −4; unimodal

13. modes are 4.7 and 5.6; bimodal

14. mode is 3; unimodal

15. modes are 4, and 10; bimodal

16. range = 50 − 0 = 50

17. range = 25 − (−4) = 25 + 4 = 29

18. range = 7.3 − 2.5 = 4.8

19. range = 16 − (−10) = 16 + 10 = 26

20. range = 500 − 0 = 500

Chapter 20 Graphical Representation of Data

Exercise 20

1. According to the graph, 50 of the 200 women responded “No” to the survey question posed.

2. According to the graph, the median annual earnings of all full-time, year-round workers, ages 25–34, with a bachelor’s or higher degree was $53,800 in the year 2015.

3. According to the graph, 29,900 (= 65% × 46,000) students enrolled at University X are freshmen or sophomores.

4. According to the graph, the small online business produced the least annual profit in 2015.

5. According to the graph, 13 of the 25 guests who attended the fundraiser for the local PAWS dog shelter were over 40 years old.

6. According to the graph, 60 of the 100 ninth-grade boys are at least 64.5 inches tall.

7. According to the graph, 10 of the 20 third graders read independently for less than 15 minutes during free time in class.