MA21-04 Maths Coming soon
Construct direct and inverse proportion equations, including powers and roots
This lesson is coming soon.
In this lesson
Construct the full equation for a direct or inverse proportion relationship — including a power or root — by finding the constant k from given data, and check the final written equation against the original statement.
What it covers
- The full round-trip: read the proportion statement, write the general form (y=kx^n or y=k/x^n, including n=1 and n=1/2 for a square root), substitute given values to solve for k, write the complete final equation
- Using the completed equation to find a new value
- The explicit final check: re-read the written equation against the original English sentence to confirm the power/root is present and the direction (direct/inverse) is correct
- Direct proportion to a power or root (y proportional to x^2, x^3, or root x) — Higher tier
Key words
For: AQA GCSE 8300, Edexcel GCSE 1MA1, Eduqas GCSE C300, Cambridge IGCSE 0580, Edexcel IGCSE 4MA1, OCR GCSE J560
On the specification
| Board | Spec | Statement |
|---|---|---|
| AQA GCSE 8300 | R13 | Understand that X is inversely proportional to Y is equivalent to X is proportional to 1/Y |
| Edexcel GCSE 1MA1 | R13 | Understand that X is inversely proportional to Y is equivalent to X is proportional to 1/Y; interpret equations that describe direct and inverse proportion |
| Eduqas GCSE C300 | HR14 | Understand that X is inversely proportional to Y is equivalent to X is proportional to 1/Y; construct and interpret equations that describe direct and inverse proportion |
| Cambridge IGCSE 0580 | E2.8 | Express direct and inverse proportion in algebraic terms and use this form of expression to find unknown quantities. |
| Edexcel IGCSE 4MA1 | H2.5A | Set up problems involving direct or inverse proportion and relate algebraic solutions to graphical representation of the equations |
| OCR GCSE J560 | 5.02a | Solve simple problems involving quantities in direct proportion including algebraic proportions. |
For teachers
This GCSE Maths lesson teaches construct direct and inverse proportion equations, including powers and roots. By the end, students should be able to construct the full equation for a direct or inverse proportion relationship — including a power or root — by finding the constant k from given data, and check the final written equation against the original statement. It works through two worked examples and the mistakes examiners report.