Answer: m1 × m2 = -1.
- A m1 = m2
- B m1 + m2 = 0
- C m1 × m2 = -1
- D m1 × m2 = 1
Correct answer: C. m1 × m2 = -1
Explanation: Perpendicular lines: m1 × m2 = -1. If one slope is 2, the perpendicular slope is -1/2.
The slope of a line is the ratio of vertical change (rise) to horizontal change (run) between any two points on it - equivalently, the tangent of the angle θ the line makes with the positive x-axis.