Proportion Solver (Rule of Three)

Solve for unknown variable X in proportion equations a : b = c : x.

How It Works & Processing Standards

Enter values above to calculate results automatically. Check each input field for guidance and units.

Your input data is never sent to any server and is securely processed on your device.

Current Limits

  • Maximum input length: 100,000 characters

Proportion Solver (Rule of Three) is a 100% free, browser-based online utility. All calculations and file conversions run locally inside your browser (Local-First) without sending data to remote servers, keeping your documents and inputs strictly private.

How to Use Proportion Solver (Rule of Three)

  1. 1
    Input Known ValuesFill in terms a, b, and c.
  2. 2
    CalculateSolve for x using cross multiplication.
  3. 3
    Inspect SolutionRead the exact calculated value for x.

Common Use Cases

  • Rescaling culinary recipe quantities for larger gatherings
  • Converting map scale distances to physical kilometers
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