Rule of three calculator
Solve a direct rule of three: if A is to B, C is to what.
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is toasis to X
X
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Solve a direct rule of three: if A is to B, C is to X. One of the most commonly used calculations in everyday life.
Calculates X = (B x C) / A, the standard formula for a direct rule of three (direct proportionality).
Use cases
- Scaling a recipe to a different number of servings.
- Converting proportional quantities in a formula.
- Solving school proportionality problems.
How it works
- 1
Enter A and B
Type the first two values of the known ratio.
- 2
Enter C
Type the third value and get X instantly.
Frequently asked questions
- Does it work for inverse proportionality?
- No, this calculator only solves direct proportionality (simple direct rule of three).
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