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Proportion Calculator
Solve proportions and find missing values in equivalent ratios.
About This Calculator
Proportions are equations stating two ratios are equal. Cross-multiplication (ad = bc) is the universal solution method. Recipe scaling, map reading, exchange rates, and speed problems all involve proportion. If 3 workers complete a job in 4 days, 9 workers finish in X = 4×3/9 = 1.33 days.