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Rule of Three Calculator
If A relates to B, what relates to C? Works for direct and inverse proportion.
FAQ
What is the rule of three?
A method to find a fourth value from three known values: if 3 items cost 1.50, 5 items cost 1.50 ÷ 3 × 5 = 2.50.
What is inverse proportion?
More of one means less of the other: if 4 workers need 6 days, 8 workers need 6 × 4 ÷ 8 = 3 days.