Rule of Three Calculator
Solve proportions instantly with our Rule of Three calculator. Enter three values to find the fourth unknown value.
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As
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Formula Applied:
X = (B × C) ÷ A
X = (20 × 30) ÷ 10 = 60
What is the Rule of Three?
The Rule of Three is a mathematical method for finding a fourth, unknown value when three values are known and they are proportional. It is widely used for solving problems related to percentages, ratios, scaling recipes, and currency conversion.