Assume we have two lines which are perpendicular. If one line has a slope of 3, what is the slope of the other line? Enter your answer as an integer or fraction in lowest terms.

Perpendicular lines have slopes that are reciprocals and opposite signs. Reciprocal means to flip a fraction. If it is a whole number, put it over 1 and flip it. Then change the sign to its opposite.

You could also do - 1 divided by the slope you want to be perpendicular to.