Home > APCALC > 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 determine the slope of the perpendicular line?

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.