Question

If two lines are perpendicular, how are their slopes related?

Answer 1

If two lines are perpendicular and neither one is vertical, then one of the lines has a positive slope, and the other has a negative slope. ... Theorem 105: If two nonvertical lines are perpendicular, then their slopes are opposite reciprocals of one another, or the product of their slopes is −1.

Answer 2

The slopes will be opposite reciprocals.

This means that they will be the opposite sign and the reciprocal.

For example, if the slopes of 2 eqautions are 3 and -1/3, they are perpendicular.