PDF download Download Article PDF download Download Article

Finding the slope of a line is an essential skill in coordinate geometry, and is often used to draw a line on graph, or to determine the x- and y-intercepts of a line. The slope of a line is a measure of how steep the line is, [1] which is found be determining how many units the line moves vertically per how many units it moves horizontally. You can easily calculate the slope of a line using the coordinates of two of its points.

Part 1
Part 1 of 2:

Setting up the Problem

PDF download Download Article
  1. Slope is defined as “rise over run,” with rise indicating vertical distance between two points, and run indicating the horizontal distance between two points. [2]
  2. These can be any points the line runs through.
    • You can also use this method if you are given two points on the line, without having the line graphed in front of you.
    • Coordinates are listed as , with being the location along the x, or horizontal axis, and being the location along the y, or vertical axis.
    • For example, you might choose points with coordinates and .
    Advertisement
  3. One point will be point 1, and one point will be point 2. It doesn’t matter which point is which, as long as you keep them in the correct order throughout the calculation. [3]
    • The first point’s coordinates will be , and the second point’s coordinates will be
  4. The formula is . The change in y-coordinates determines the rise, and the change in x-coordinates determines the run. [4]
  5. Advertisement
Part 2
Part 2 of 2:

Finding the Rise and Run

PDF download Download Article
  1. Make sure you are not using the x-coordinates, and that you are substituting the correct y-coordinates for the first and second points. [5]
    • For example, if the coordinates of your first point are , and the coordinates of your second point are , your formula will look like this:
  2. Make sure you are not using the y-coordinates, and that you are substituting the correct x-coordinates for the first and second points. [6]
    • For example, if the coordinates of your first point are , and the coordinates of your second point are , your formula will look like this:
  3. This will give you your rise. [7]
    • For example, if your y-coordinates are and , you would calculate .
  4. This will give you your run. [8]
    • For example, if your x-coordinates are and , you would calculate .
  5. This result will give you the slope of your line. [9]
    • For complete instructions on how to reduce a fraction, read Reduce Fractions .
    • For example, can be reduced to , so the slope of a line through points and is .
  6. A slope can be positive or negative. A line with a positive slope moves up left-to-right; a line with a negative slope moves down left-to-right.
    • Remember, if the numerator and denominator are both negative, then the negative signs cancel out, and the fraction (and slope) is positive.
    • If either the numerator or the denominator is negative, then the fraction (and slope) is negative.
  7. To do this, look at the rise and run you calculated for your slope. Starting at your first point, count up the rise, then over the run. Repeat counting up the rise and over the run until you reach your second point.
    • If you do not reach your second point, then your calculation is incorrect.
  8. Advertisement

Community Q&A

Search
Add New Question
  • Question
    What does a negative slope look like?
    Community Answer
    A negative slope moves down, left-to-right.
  • Question
    Can you do this without a graph, like when they give you 2 coordinates?
    Emma Han
    Community Answer
    Yes you can. The graph is only there to help you. You can only find the gradient if they give you 2 points.
  • Question
    How do you compute slope with (-6,3) and (2,9)?
    GB742
    Top Answerer
    Use the formula m = (y2 - y1)/(x2 - x1). In this example: (9 - 3)/(2 - -6) = (6)/(8). Therefore, the slope of the line connecting (-6,3) and (2,9) is 6/8.
See more answers
Ask a Question
      Advertisement

      Tips

      • Slope is often labeled . Thus, once you have determined the slope of the line, you can work with the equation of a line, which is , where is the slope of the line and is the y-intercept.
      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Thanks for submitting a tip for review!
      Advertisement

      Expert Interview

      Thanks for reading our article! If you’d like to learn more about math, check out our in-depth interview with Grace Imson, MA .

      About This Article

      Thanks to all authors for creating a page that has been read 85,641 times.

      Reader Success Stories

      • Gabriel Christopherson

        Dec 16, 2020

        "I needed help on a question for math and I came to wikiHow because one of my friends said it was a great site for ..." more
      Share your story

      Did this article help you?

      Advertisement