Proportion Solver
Solve a:b = c:x and similar proportion equations with cross-multiplication steps shown.
O
M
T
Solve proportion equations a/b = c/x
Proportions state that two ratios are equal. Given three known values in a/b = c/x, cross-multiplication yields the missing fourth. Leave exactly one of a, b, c, or x blank and the tool solves for it with shown algebra steps.
How to use it
- Fill three of the four fields with numbers.
- Leave the unknown empty.
- Copy the result and steps for worksheets or recipe scaling.
For general percent change, see Percentage Change Calculator.
Frequently Asked Questions
What if two fields are blank?
The solver requires exactly one unknown; otherwise it asks you to leave a single value empty.
Can denominators be zero?
No. Division by zero is rejected with an error when it would appear in the solution.
Are steps exact?
Results use JavaScript floating-point arithmetic; repeating decimals may show rounding.
Related Tools
MCA Calculator
Bond Price Calculator
Special Characters
OPML Viewer
Break Even Calculator
531 Lifting Calculator
Hydroxychloroquine Dose Calculator
Weight Calculator
Lbs To Stone Converter
BASDAI Score Calculator
Coin Rotation Paradox Calculator
Step Up SIP Calculator
FEV1 FVC Ratio Calculator
GTIN Check Digit Calculator
Shannon Entropy Calculator
Aquarium Volume Calculator
Half Birthday Calculator
Lubricant Cost to Run Calculator
Percent Difference Calculator
Every Second Calculator