Using Two Points to Find Slope                              Page 2 of 5

The Slope Formula

Remember, slope is "Rise over Run."  On a graph when you find the rise, you're finding the vertical change.  Subtracting the y-coordinates will give you the rise without needing a graph.  Subtracting the x-coordinates will give you the amount of horizontal change, the run.  

​When you use the formula, make sure to subtract the y-values in the numerator and subtract the x-values in the denominator.  It doesn't matter which point you call Point 1 or Point 2 as long as you subtract in the same order at each step.

When using the formula, follow the steps below:
Step 1: Label the points.
Step 2: Plug the values into the formula.
Step 3:​ Write the slope as a simplified fraction.

Example 1

Find the slope of the line through the points (2,5) and (4,8).

Step 1: Label the points.  It doesn't matter which one you pick as "Point 1" and "Point 2."  Remember the x's are listed first in an ordered pair and the y's are listed second.

Step 2: ​Plug in the values.  Subtract the y's on the top, subtract the x's on the bottom. Make sure to subtract in the same order in the numerator and denominator.

Step 3: Make sure your answer is simplified.  3/2 cannot be reduced, so we leave the answer as 3/2.

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