There are several methods you can use to determine the slope of a line when you are given its graph. In this section, you will study two different methods.
Choose two points from the line of the graph to determine the rise over run. View the videos below to learn more about this method.
Source: Given a Graph, Find the Slope, Davitily, YouTube
Source: Finding the Slope Given a Line, Davitily, YouTube
If you are using the rise over run method for determining the slope from a graph, how can you tell from looking at the line if the slope will be positive or negative?
Interactive popup. Assistance may be required. The run will always be positive because you are moving from left to right on the graph. The direction of the rise will tell you if the slope will be positive or negative. If the rise is positive, the slope will be positive, and the line will move upward from left to right. If the rise is negative, the slope will be negative, and the line will move downward from left to right.
Choose two points from the line of the graph. Given the coordinates of those two points, use the slope formula m = (y sub 2 minus y sub 1) over (x sub 2 minus x sub 1) y2 − y1 x2 − x2 to determine the slope.
View the video below to learn more about this method.
Source: Finding the Slope Given Two Points, Davitily, YouTube
How does using the slope formula compare to using the rise over run method?
Interactive popup. Assistance may be required. The slope formula uses coordinates to calculate the change in the y-direction (rise) and the change in the x-direction (run). The ratio of these two differences is the same as the ratio of the rise and the run of a graph.
Click on the image below to open a new website and practice determining the slope given a graph. Complete problems 1-10. Enter your answers into the box on the left. Check your answers once you are done.
