Question

A line has a slope of 9 what is the slope of a line it is perpendicular to this line? *

9
-9
1/9
-1/9

Answer 1

Answer: -1/9

Explanation: Perpendicular lines have negative reciprocal slopes.

A negative reciprocal slope is a fancy way of

saying flip the fraction and change the sign.

Notice that our slope is an integer.

We can turn it into a fraction by putting it over 1.

So we have 9/1.

A line perpendicular to this would be a negative reciprocal.

So flip the fraction, giving us 1/9, and change the sign to get -1/9.