### Home > CALC > Chapter 2 > Lesson 2.3.3 > Problem2-129

2-129.

What is the relationship between the slopes of perpendicular lines? If you know the slope of one of the lines, how can you find the slope of a line perpendicular to it?

Choose a number to represent the slope of line $A$.
Divide $−1$ by your number.
Simplify.
That is the slope of line $B$.
How do the slopes compare?

The slopes of perpendicular lines are negative reciprocals.