Question

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

Answer 1

-3

Explanation:

Perpendicular slopes are opposite reciprocals of each other.

Opposites: positive vs negative

The perpendicular slope of a positive slope must be negative, and vice versa.

Reciprocals: multiplicative inverses (the numbers will multiply to 1)

Examples of reciprocals:

`2, 1/2 rarr` `2*1/2=1`

`1/3, 3 rarr` `1/3*3=1`

The opposite of `1/3` is `-1/3`, the reciprocal of `-1/3` is `-3`.

Answer 2

`-3`

Explanation:

The slope of two perpendicular lines are negative reciprocals of each other. That means that you flip the fraction upside down and take the opposite of it. The reciprocal of `1/3` is `3`. The opposite of `3` is `-3`. So the slope is `-3`.