GCSE Maths Revision Guide
Parallel & Perpendicular Lines
Identify parallel and perpendicular lines from their equations. This free GCSE Maths module combines short explanations, worked examples, flashcard-style recall, and timed practice so students can revise the topic without creating an account.
Foundation Skills
Parallel Lines
Parallel lines have the same gradient.
Example: y = 3x + 1 and y = 3x − 5 are parallel (both m = 3)
Higher Skills
Perpendicular Lines
Perpendicular gradients multiply to −1.
Formula: m₁ × m₂ = −1
Example: y = 2x + 1 → perpendicular m = −1/2
Finding Equations
Use y − y₁ = m(x − x₁) with the perpendicular gradient and a given point.
Example: Perpendicular to y = 3x, through (6, 1): m = −1/3 y − 1 = −1/3(x − 6) y = −x/3 + 3