1. Finding The Slope of a Line
Jennifer Prince 6/18/03

2. The slope we are studying is associated with the graph of a line.

3. Definitions of Slope The tilt or inclination of a line
The ratio of vertical change to horizontal change.
The change in y over the change in x
Allow students time to copy
May need to review that a ratio is a comparison of numbers

4. Tilt or Inclination Discuss positive and negative slope.
Discuss when slope equals 0 and is undefined.

5. Vertical Change Horizontal Change
This ratio is also known as
Rise
Run

6. How many points do you need to draw a line?
One
Two
Three
Quiz students

7. Graph (3,2) and (-1,-1)
Remember to click to make each part appear

8. Draw a line through the points.
Line will appear automatically

9. Now that we have our line lets find its slope.
Remember we are finding the following ratio:
Vertical or Rise
Horizontal Run

10. Vertical Change or the Rise3
Discuss vertical change

11. Horizontal Change or the Run4 3
Discuss horizontal change

12. Vertical Rise Horizontal Run3 4
May need to remind students that a ratio is a comparison of two numbers

13. Find the slope of the following line.

14. The slope is… 1 2

15. Find the slope of the line.

16. The slope is…. -3
Discuss why the slope is negative and that –3/1 reduces to –3.

17. Find the slope of these lines.
Have students practice.

18. The slope is…
Black line 3
Red Line 1
Blue Line -1/2

19. Find the slope of these lines

20. The slope is…
Orange line 0
Green Line Undefined

21. Let’s draw a line using slope.
What else do you think you need besides the slope in order to draw a line?
A point!

22. If you know the slope and one point on the line you can draw the line
If you know the slope and one point on the line you can draw the line. Example: slope is 1/3 and the point (-2,-1)

23. Now you draw a line. Given: slope is 2/3 and the point is (1,0)

24. The graphs are…

25. Change in y over the change in x
The formula for finding
the slope of a line.