Direct and Inverse Proportion Calculator
Use one known x,y pair to find the constant of direct or inverse proportion, calculate another y and compare a value table with the graph.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
For direct proportion, divide the known y by its x to obtain k, then multiply k by the new x. For inverse proportion, multiply the known x and y for k, then divide k by the new x.
Direct: k=y₀/x₀, y=kx. Inverse: k=x₀y₀, y=k/x, x≠0.
Worked example
The known pair x=2, y=6 gives direct proportion y=3x, so x=4 gives y=12. For inverse proportion the same pair gives y=12/x, so x=4 gives y=3.
Assumptions and input details
This assumes the selected proportional relationship; one data pair cannot establish that a real process follows the model. Inputs must be finite and within ±1e6, with nonzero known x. In inverse mode the known y and queried x must also be nonzero. The inverse graph has separate negative and positive branches and never joins across x=0. Its plotted x values stop at 1% of the horizontal half-range near zero; the formula and table still identify the excluded zero. A zero direct-proportion constant is allowed and produces y=0.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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