Proportion Calculator
Solve a/b = c/d. Leave exactly one of a, b, c, d blank.
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How to use Proportion Calculator
- Enter a, b, c. Leave a field blank only when the page says the value is missing.
- Read the result rows under the form. Errors appear in the status line. Nothing is uploaded.
- Rounding follows IEEE floating point in this browser unless the page says it uses integers or BigInt.
Proportion Calculator
Solve one missing term
| Computes | Solve a/b = c/d. Leave exactly one of a, b, c, d blank. |
|---|---|
| Includes | Solve one missing term |
| Includes | Cross multiply |
| Engine | percentage |
| Upload | None |
| Advice | Arithmetic only |
What Proportion Calculator is
Cross multiply: a × d = b × c. The missing term is isolated. A zero in a denominator position is rejected.
The formula runs in this tab. CZNull does not receive the numbers.
How this page computes
Related: ratio for two terms, percentage for parts of 100.
Entities and related jobs
Solve a/b = c/d. Leave exactly one of a, b, c, d blank. Named features: Solve one missing term, Cross multiply.
See also Ratio Calculator, Percentage Calculator, Triangle Calculator, Scientific Calculator, Fraction Calculator, GCD Calculator.
Use cases
Similar triangles, recipes scaled up, and unit rates. Geometry side lengths that form a triangle are on the triangle page.
Limits
Invalid input appears in the status line. IEEE floating point applies unless a row says otherwise. CZNull does not receive the numbers.