Solve missing terms, test proportions, and compare ratio balance clearly. See steps, exports, graphs, and examples for faster learning.
Enter three known values and leave one blank to solve it. You can also enter all four values to verify whether both ratios are equal.
Core proportion rule: a / b = c / d
Cross multiplication: a × d = b × c
Missing term formulas:
The tool compares both cross products. If they are equal, or nearly equal within your tolerance, the ratios form a valid proportion.
| Example | a | b | c | d | Purpose | Expected Result |
|---|---|---|---|---|---|---|
| Example 1 | 4 | 5 | 8 | 10 | Verify equal ratios | Valid proportion |
| Example 2 | 3 | 7 | 9 | Solve missing d | 21 | |
| Example 3 | 6 | 15 | 10 | Solve missing a | 9 | |
| Example 4 | 5 | 9 | 7 | 11 | Check mismatch | Not equal |
It compares two ratios by multiplying diagonally. For a / b = c / d, you test whether a × d equals b × c.
Yes. Enter any three known values and leave one field blank. The calculator rearranges the proportion and solves the missing term.
Tolerance helps when numbers are rounded decimals. Two products may differ slightly from rounding, yet still represent the same practical proportion.
Ratios with zero denominators are undefined. The tool blocks those cases during verification to avoid invalid division results.
Yes. The calculator accepts integers, decimals, and negative numbers. It then computes the ratio and cross products using those values.
The graph compares the two cross products, a × d and b × c. Equal bars indicate a balanced proportion.
The CSV file includes the completed values, solved term, ratios, cross products, difference, and final status. It is useful for records and reports.
It helps with fractions, similar shapes, scale drawings, recipe scaling, unit conversions, ratio checks, and classroom proportion practice.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.