A slope value indicates the ratio of the rise to run for a line on a graph. A For Every ... statement can be used to communicate this rise per run ratio. To say that a slope of a position-time graph is 4.0 m/s is like saying that for every 1 second change in time, there is a 4.0-meter change in position.
 

The slope is the "rise per run" ratio for a line on a graph.  Its value indicates how high the line rises upwards along the vertical axis for every 1 unit of run along the horizontal axis. A For Every ... statement is a way of expressing this idea. For instance, a position-time graph may have a slope of 25 cm/s. This indicates that the line rises 25 cm upwards along the vertical axis for every 1-second along the horizontal axis. In other words, for every 1-second change in time, there is a 25-cm change in position. You will need to communicate this understanding by selecting the Multiple Choice option that matches the slope of the line.

Calculating Slope
Of course to identify the correct For Every ...  statement, you will need to calculate the slope of the line. So we will repeat here the same directions that we provided in Activity 1 of this Concept Builder.

1. Select two points on the line (they do not need to be data points). Write down the coordinates of these two points. 
2. Find the change in the Y-coordinate (∆Y) by subtracting the Y-coordinate of the first point from the Y-coordinate of the second point.
3. Find the change in the X-coordinate (∆X) by subtracting the X-coordinate of the first point from the X-coordinate of the second point.
4. Calculate the ratio of ∆Y to ∆X. That is, divide the ∆Y value by the ∆X value.

Once you have calculated the slope, find the For Every ... statement that matches this slope value.
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