This deep dive covers Advanced: Complex Proportions 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 12 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Advanced: Complex Proportions
More complex relationships include:
- Square relationships: y ∝ x² (area problems)
- Cube relationships: y ∝ x³ (volume problems)
- Square root: y ∝ √x (some physics laws)
- Combined: z ∝ xy (z proportional to product of x and y)
Key insight: The constant k gives the relationship its "strength"
If y ∝ x² and k = 3, then doubling x makes y four times bigger (×4), but also three times that due to k
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.