Proportion Calculator

Solve a proportion (a/b = c/d) for the missing value using cross-multiplication.

D (missing value)

16.0000

A/B0.750000
C/D0.750000
Cross Product (A*D)48.0000

D (missing value) vs A (numerator 1)

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Formule

## How to Solve a Proportion ### Formula **If A/B = C/D, then D = (B * C) / A** A proportion is an equation stating that two ratios are equal. Cross-multiplication gives A*D = B*C. Solve for any missing value by rearranging. This is fundamental to scaling, unit conversion, and similar triangles.

Exemple Résolu

If 3/4 = 12/x, find x.

  1. 01Cross-multiply: 3 * x = 4 * 12
  2. 023x = 48
  3. 03x = 48 / 3 = 16
  4. 04Check: 3/4 = 0.75, 12/16 = 0.75. Confirmed.