# What is the slope of a line that is perpendicular to a slope of 1/3?

Jul 27, 2017

The slope of a line perpendicular to one with the slope of $\frac{1}{3}$ is $- 3$. See explanation.

#### Explanation:

If two lines are perpendicular, then the product of their slopes equals to $- 1$. So if one of the slopes is $\frac{1}{3}$, then we can calculate the second slope using the formula:

## ${m}_{1} \times {m}_{2} = - 1$

Here we have:

$\frac{1}{3} \times {m}_{2} = - 1$

${m}_{2} = - 3$