Finding The
Slope of a Line
Jennifer Prince 6/18/03
Slopes are commonly
associated with mountains.
The slope we are studying is
associated with the graph of a
line.
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
Tilt or Inclination
Vertical Change
Horizontal Change
This ratio is also known as
Rise
Run
How many points do you need to
draw a line?
• One
• Two
• Three
Graph (3,2) and (-1,-1)
Draw a line through the points.
Now that we have our line lets
find its slope.
Remember we are finding the following ratio:
Vertical
or
Rise
Horizontal
Run
Vertical Change
or the Rise
3
Horizontal Change
or the Run
4
3
Vertical
Horizontal
Rise
Run
3
4
Find the slope of the following
line.
The slope is…
1
2
Find the slope of the line.
The slope is….
-3
Find the slope of these lines.
The slope is…
• Black line
3
• Red Line
1
• Blue Line
-1/2
Find the slope of these lines
The slope is…
• Orange line
0
• Green Line
Undefined
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!
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)
Now you draw a line.
• Given: slope is 2/3 and the point is (1,0)
• Given: slope is –3 and the point is (–2,4)
• Given: slope is 1 and the point is (2,3)
The graphs are…
Student Activity
You will now receive a worksheet.
You are to find the slope of a line and
draw a line given the slope and a
point. Turn the worksheet in when
completed.
Work Time
Change in y over the change in x
The formula for finding
the slope of a line.
Class Activity
Click on the following link
for slope practice.
Closing Activity
You will receive a second worksheet.
Given 2 points, find the slope using
the slope formula. You will turn in
the worksheet.