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How to Solve Proportions
Formula
A proportion states that two ratios are equal: a/b = c/d. Cross-multiply to solve: a * d = b * c.
Enter three known values and this calculator finds the fourth by rearranging the cross-multiplication equation.
Common use cases:
- Recipe scaling and conversions
- Map scale distance calculations
- Unit conversion problems
Frequently Asked Questions
Dr. David Park
Applied Mathematician, PhD Mathematics
David holds a PhD in Applied Mathematics from MIT. He has published research on numerical methods and computational algorithms used in engineering and scientific calculators.
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