Parallel and Perpendicular Lines

Parallel lines

Parallel lines have the same gradient.

If y = 2x + 3, then a parallel line could be y = 2x - 1

Perpendicular lines

If two lines are perpendicular, the product of their gradients = -1.

If gradient of line 1 = m, then gradient of perpendicular = -1/m

Example: If m = 2, perpendicular gradient = -1/2

If m = -3/4, perpendicular gradient = 4/3

Exception: Horizontal line (m = 0) is perpendicular to vertical line (m undefined).

Discussion

How was the lesson? Discuss Lesson

Related Exercises

Parallel and perpendicular

Answer the following:Line A: y = 3x + 2. Give the gradient of a line parallel to A.Line B: y …

View Exercise Submit Exercise