### Home > GB8I > Chapter 3 Unit 4 > Lesson INT1: 3.1.3 > Problem3-32

3-32.

Robert believes the lines graphed at right are perpendicular, but Mario is not convinced. What is the slope of each line? Explain how you know whether or not the lines are perpendicular.

Remember that if two lines are perpendicular, the product of their slopes is $−1$.