Graphing—continued

The Slope of a Line Graph

Notice that it doesn’t matter which two points on the line you choose: the slope of a straight line is always the same. This example is a fairly simple one, with nice, small numbers. Sometimes it’s not so easy to determine the rise and run by inspection. In these cases, we use a more comprehensive formula.
Choose two points on the graph and label them P1 and P2. The coordinates of these points are P1(x1, y1) and P2(x2, y2). Using the definitions of rise and run, we can say that: slope = rise/run = (y2 – y1)/(x2 – x1) Let’s try an example on the next page.

All content copyright 2006 Province of BC