2. Main Idea and New Vocabulary Key Concept: Slope Example 1: Find Slope
Example 2: Interpret Slope
Lesson Menu

3. Identify slope using tables and graphs.
Main Idea/Vocabulary

4. Key Concept

5. Find Slope
EARNINGS The table below shows the relationship between the number of hours Carlos works and the amount of money that he earns. Graph the data. Then find the slope of the line. Explain what the slope represents.
Example 1

6. Find Slope Definition of slope Use (3, 45) and (6, 90). Simplify.
The slope is 15. The slope represents the amount earned per hour. So, for every hour Carlos works he earns $15.
Example 1

7. Find Slope Graph the data. Answer:
The slope of the graph is 15 and represents the amount earned per hour.
Example 1

8. C. The slope 15 represents the number of pages read per hour.
READING The table below shows the relationship between the hours Joe reads and the number of pages he reads. Graph the data. Then find the slope of the line. Explain what the slope represents.
A. The slope 2 represents the number of minutes it takes to read one page.
B. The slope 3 represents the number of minutes it takes to read one page.
C. The slope 15 represents the number of pages read per hour.
D. The slope 20 represents the number of pages read per hour.
Example 1 CYP

9. Interpret Slope
AQUARIUMS Nina drains a 20-gallon aquarium at a rate of 0.5 gallon per minute. Draw a graph of the water in the aquarium versus time. Find the numerical value of the slope and interpret it in words.
Graph the data. There are 20 gallons of water in the tank and it drains at a rate of 0.5 gallon per minute, or 1 gallon every two minutes.
Example 2

10. Interpret Slope
Answer: The slope of the line is the rate at which the water drains, or – This is a negative slope and therefore a negative rate of change.
Example 2

11. B. The slope 20 represents the amount of money he has paid.
PAYMENTS Nick is making payments on a stereo he purchased for $200. He is paying $20 every week toward the balance of the purchase price. Draw a graph of the money he still owes versus time. Find the numerical value of the slope and interpret it in words.
A. The slope 10 represents the number of payments he needs to make to pay off the balance.
B. The slope 20 represents the amount of money he has paid.
C. The slope –20 represents the rate at which the amount he still owes falls each week.
D. The slope –30 represents the interest rate on the balance he owes.
Example 2 CYP