This key facts covers Key Facts within Proportion Graphs for GCSE Mathematics. Revise Proportion Graphs in Ratio & Proportion for GCSE Mathematics with 14 exam-style questions and 4 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 2 of 6 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 2 of 6
Practice
14 questions
Recall
4 flashcards
Key Facts
| Symbol | y ∝ x means "y is directly proportional to x" |
| Formula | y = kx, where k is the constant of proportionality |
| Graph | A straight line through the origin (0,0) |
| Key Feature | y/x always equals the same value (k) |
| Higher: y ∝ x² | y = kx² (quadrupling x means y × 4²) |
Keep building this topic
Read this section alongside the surrounding pages in Proportion Graphs. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Proportion Graphs
Which of the following describes the graph of a direct proportion relationship?
Aisha says: 'Because the graph of y against x is a straight line, y must be directly proportional to x.' Is Aisha correct? Explain your answer.
Quick Recall Flashcards
14 questions on Proportion Graphs — practise free
Instant marking, adaptive difficulty, and 4 spaced repetition flashcards. Free until your GCSEs.
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