# How do you find the slope that is perpendicular to the line y= -1?

##### 1 Answer
Aug 5, 2017

See a solution process below:

#### Explanation:

The line described by $y = - 1$ is a horizontal line where $y$ is the same value for each and every value of $x$. Horizontal lines, by definition have a slope of $0$.

A perpendicular line therefore will be a vertical line.

Vertical lines, by definition, have an undefined slope.