Understanding the gradients of perpendicular lines.
- Lesley Cowey
Understanding why the gradient of a perpendicular line is the negative reciprocal of the gradient of the original line.
Rotate the line (use the slider) and the triangle which defines its gradient. What happens to the 'rise' and the 'run' as the lines become perpendicular? What happens to the sign (positive or negative) of the gradient of the original line?