7th Grade Math

Extra Practice begins on page EP2.

Lesson 3A Variation 403

= Step-by-Step Solutions begin on page R1.

Extra Practice begins on page EP2.

Use a graph to solve Exercises 3 and 4.

3. The table shows the relationship between
   Celsius and Fahrenheit temperatures.

Temperature

Celsius Fahrenheit

032

10 50

20 68

30 86

40 104

a. Make a graph of the data.

b. Suppose the temperature is 25° Celsius.

Estimate the temperature in Fahrenheit.

4. SCHOOLS The graph shows the number of
   students enrolled at Yorktown Middle
   School over a five-year period. Predict the
   school’s enrollment in 2015.

Number of Students

2,000

2,250

2,500

2,750

Year

20062007200820092010

Yorktown Middle School

Use any strategy to solve Exercises 5–11.

5. ALGEBRA What are the next two numbers
   in the pattern 8, 18, 38, 78, ...?


6. FARMING A farmer sells a bushel of corn
   for $3. Suppose the farmer wants to earn
   $165 from bushels of corn sales on
   Saturday. How many bushels does he need
   to sell to make his goal?
   7. EXERCISE Flora walked 8 minutes on
   Sunday and, each day, plans to walk twice
   as long as she did the previous day. On
   what day will she walk over 1 hour?
   8. OIL SPILLS The graph shows the number of
   oil spills each year.

Oil Spills

Number of Oil Spills

10

5

15

20

25

30

35

Year

1998 2000 2002 2004 2006 2008

a. What does the graph indicate happened

from 2002 to 2004?

b. What is the overall trend in the data?

c. Is the relationship linear?

d. Explain the difference between a linear

relationship and a trend.

99 HELICOPTERS A helicopter has a maximum

freight capacity of 2,400 pounds. How

many crates, each weighing about

75 pounds, can the helicopter hold?

10. SKATING Moses and some of his friends
    are going to the movies. Suppose they
    each buy nachos and a beverage. They
    spend $36. How many friends are going
    to the movies with Moses?

Movie Costs

Item Price

Ticket $6.00

Beverage $2.25

Nachos $3.75

11. NUMBER THEORY A whole number is
    squared and the result is 324. Find the
    number.

• Use a graph.


• Guess, check, and revise.


• Look for a pattern.


• Choose an operation.

402_403_C07_PSI_895130.indd 403 12/31/09 4:28 PM