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Ratio & ProportionHigh Exam FrequencyAQAEdexcelOCRWJEC

Direct Proportion

Revise Direct Proportion in Ratio & Proportion for GCSE Mathematics with 15 exam-style questions and 12 flashcards. This is a high-frequency exam topic, so students should expect to explain it clearly under timed conditions.

Study this topic

1

What is Direct Proportion?

Introduction2

Key Features of Direct Proportion

Key Facts3

Method 1: The Multiplier Method

Deep Dive4

Method 2: The Unitary Method

Deep Dive5

Worked Example 1: Using the Formula

Notes6

Worked Example 2: Unitary Method

Notes7

Worked Example 3: Best Buy Problem

Notes8

Common Mistakes to Avoid

Exam Tips

Sample Flashcards

What does the symbol ∝ mean?
'is proportional to' y ∝ x means 'y is proportional to x' This is equivalent to writing y = kx for some constant k.
What does the graph of y = kx look like?
A straight line passing through the origin (0, 0). The gradient of the line equals k. If the line does NOT pass through (0,0), it is NOT direct proportion.

Sample Questions

Which of the following correctly reads the mathematical statement y ∝ x?

  • A. y is inversely proportional to x
  • B. y is directly proportional to x
  • C. y equals x
  • D. y is greater than x
1 markfoundation

Explain what it means for y to be directly proportional to x. Your answer should refer to the equation and the graph.

2 marksstandard

15

exam-style questions

12

revision flashcards

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Inverse Proportion