Proportion Calculator
Solve A is to B as C is to X. Handy for scaling recipes, maps, drawings and unit rates.
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X
- Proportion
- Ratio (B ÷ A)
- Check
- Work
Saved Calculations
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How to Solve a Proportion
A proportion says two ratios are equal. Cross multiplying turns it into a simple equation.
A / B = C / X → A × X = B × C → X = B × C ÷ A
Worked Example
Tips
Keep units lined up: if A is cups of flour and B is servings, C must be cups too. Example: 2 cups for 6 servings is 2/6 = C/X; for 15 servings, set A = 6, B = 2, C = 15 to get X = 5 cups.