AbraCalc

1/3 = x/9 — Solve for the Missing Value

Solving 1/3 = x/9 gives x = 3.

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How to use this tool

  1. Enter A and B (the known fraction).
  2. Enter C (the denominator of the unknown fraction).
  3. Read X, the missing numerator.

Simple proportions like 1/3 = x/9 are common in everyday maths — verify your answer here.

Frequently asked questions

How do I solve a proportion?
Cross-multiply: A/B = X/C means A × C = B × X, so X = (A × C) / B. Example: 3/4 = X/12 → X = (3 × 12) / 4 = 9.
What is a proportion used for?
Proportions are used in scaling recipes, map distances, currency conversions, mixing solutions, and calculating probabilities.