Free Proportion Solver
Solve for the missing value in a/b = c/d.
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Inputs
Result
Missing value (D)
12.0000
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Short answer
Solve for the missing value in a/b = c/d.
What is the Proportion Solver?
Solve for the missing value in a/b = c/d.
How does the Proportion Solver work?
Enter the inputs above and read the result.
Formula
Variables
a,b,c,dThe four terms of the proportion
Explanation
Cross-multiplication lets you isolate and solve for any one unknown term in a proportion.
Examples
Applications
Advantages
Limitations
Common mistakes
Tips
Related concepts
The Proportion Solver sits inside the Math Calculators hub, in the algebra & equations cluster. Solving for unknowns and manipulating expressions. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.
Practical use cases and industry applications
Understanding Proportion Solver
Solve for the missing value in a/b = c/d. Within math calculators, proportion solver belongs to the algebra & equations cluster, where it shares terminology and assumptions with closely related tools.
Learning how proportion solver is calculated
Cross-multiplication lets you isolate and solve for any one unknown term in a proportion. Working through the variables one at a time — a,b,c,d — makes the result reproducible by hand and easier to sanity-check.
Using proportion solver to make a decision
Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.
How proportion solver compares with related measures
equation, root, exponent, logarithm all describe adjacent aspects of algebra & equations. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.
Frequently asked questions
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