Mathematics for IGCSE & O level - Coordinate Geometry (Section 2 - No. 47)
If two lines are perpendicular, and one line has a gradient of -4, what is the gradient of the other line?
4
-1/4
1/4
-4
Explication
The product of the gradients of perpendicular lines is -1. The negative reciprocal of -4 is 1/4.