# LINR 1 | Lesson 2 | Try This! (Calculating Slope)

In the previous section, we used a graph to determine the relationship between the number of times a cricket chirps (in one minute) and the temperature (in degrees Fahrenheit).

$slope=\frac{\Delta y}{\Delta x} =\frac {rise}{run}=\frac {1}{4}$

In this module, we have used tables and graphs to determine slopes.  In Lesson 1, we made connections between the changes in $$y$$ and $$x$$ to develop the slope formula.

When two points can be determined in a linear relationship, using the slope formula is a quick and efficient way to calculate slope.

• The formula for finding the slope between any two points on a line, where the first point is defined as $$(x_1,y_1)$$ and the second point is defined as $$(x_2,y_2)$$,  is shown as: $slope=\frac{(y_2-y_1)}{(x_2-x_1)}$

Example:  Use the slope formula to find the slope of the line that passes through the points $$(-3, -2)$$ and $$(3, -5)$$.

• Point 1: $$(-3, -2)$$ where $$x_1=-3$$ and $$y_1=-2$$
• Point 2: $$(3, -5)$$ where $$x_2=3$$ and $$y_2=-5$$

$slope=\frac{-5-(-2)}{3-(-3)}=\frac{-5+2}{3+3}=\frac{-3}{6}=-\frac{1}{2}$

1.  Use the Slope Formula to calculate the slope between the two points from our previous graph:

Point $$1\ (80,57)$$ and Point $$2 \ (184,83)$$