AbraCalc

Proportion: 1/2 = x/10 — Solve for X

If 1/2 = x/10, then x equals 5.

Embed this tool on your site

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.

Solve any missing value in a proportion with cross-multiplication handled automatically.

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.