Calculating Slope

Calculating Slope

Slope

The ratio of the change in y-values (rise) for a segment of the graph to the corresponding change in x-values (run).

Slope is represented with the variable, m. 

The change in the y-coordinates is the rise.

The change in the x-coordinates is the run. 

The coordinates that are used when finding slope are labeled as      (x1, y1) and (x2, y2)

Multiple Choice

What is the equation for finding slope?

• $m\ =\ \frac{y2\ -\ y1}{x2\ -\ x1}$

• $m\ =\ \frac{y2\ +\ y1}{x2\ +\ x1}$

• $m\ =\ \frac{x2\ -\ x1}{y2\ -\ y1}$

• $m\ =\ \frac{x2\ +\ x1}{y2\ +\ y1}$

Finding Slope from a Graph

First, find the rise (the change in the y values)
Second, find the run (the change in the x values)

Rise = 6 - 3 = 3
Run = 8 - 4 = 4
Slope = 3/4

You can also find slope by counting spaces on the graphs. Remember, slope is rise over run.
How many spaces does the graph go up?
How many spaces does the graph go over?

The direction of the line makes a difference whether the slope is positive or negative. 
The red line shows a positive slope.
The blue line shows a negative slope.

Multiple Choice

Find the slope.

• 1/2

• 2

• -1/2

• -2

Multiple Choice

Find the slope.

• 1/2

• 2

• -1/2

• -2

Multiple Choice

Find the slope.

• 1

• -1

• 2

• -2

Multiple Choice

Find the slope.

• 1

• -1

• 2

• -2

Slope Recap

Slope = m = rise over run
Direction of line determines whether slope is posititve or negative
Slope is NOT always a whole number. Slope CAN be a fraction!