This diagram covers Visual Understanding within Proportion for GCSE Mathematics. Revise Proportion in Number for GCSE Mathematics with 12 exam-style questions and 22 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 6 of 16 in this topic. Focus on the labels, the relationships between parts, and the explanation that turns the diagram into an exam-ready answer.
Visual Understanding
Direct Proportion Graph
y = kx
• Straight line
• Passes through origin (0,0)
• Gradient = k
• As x doubles, y doubles
• As x halves, y halves
Inverse Proportion Graph
y = k/x
• Curved line (hyperbola)
• Never touches axes
• xy = k (constant)
• As x increases, y decreases
• As x doubles, y halves
Finding the Constant k
Direct: k = y/x
Inverse: k = xy
Use any known pair (x,y)
Then apply to find unknowns
Practice questions for Proportion
y is directly proportional to x. Which equation could represent this relationship?
Explain how you can tell from a graph whether two quantities are in direct or inverse proportion.