Example

Finding the Slope 23-\frac{2}{3} from a Graph

A line is graphed on the xyxy-coordinate plane passing through the points (0,5)(0, 5), (3,3)(3, 3), and (6,1)(6, 1). To find its slope, apply the four-step rise-over-run procedure.

Step 1 — Locate two points with integer coordinates. The points (0,5)(0, 5) and (3,3)(3, 3) both have integer coordinates. The leftmost point is (0,5)(0, 5).

Step 2 — Sketch a right triangle. Starting at the left point (0,5)(0, 5), draw a vertical leg downward to (0,3)(0, 3) and then a horizontal leg to the right to reach (3,3)(3, 3).

Step 3 — Count the rise and the run. The vertical leg goes from 55 down to 33, so the rise is 2-2 (negative because the line moves downward). The horizontal leg goes from 00 to 33, so the run is 33.

Step 4 — Take the ratio of rise to run:

m=riserun=23=23m = \frac{\text{rise}}{\text{run}} = \frac{-2}{3} = -\frac{2}{3}

The slope of the line is 23-\frac{2}{3}.

To verify, use a different pair of points on the same line: (3,7)(-3, 7) and (6,1)(6, 1). The rise is 6-6 and the run is 99, giving m=69=23m = \frac{-6}{9} = -\frac{2}{3}. This confirms an important property: no matter which two points on a line are chosen, the calculated slope is always the same.

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Updated 2026-05-03

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