### Rule of three - inverse proportion

The rule of three is a method to solve proportions.
If you have three numbers: a, b, c, such that, (a/b = c/x) you can calculate the unknown value (x).

**Inverse Proportion**

When, the increase of a quantity , causes a decrease in the other one , or by the contrary, a decreasing causing the
increase in the other one, this is, an inverse proportion. So, the expression: a/b = c/x changes to: (b/a = c/x) because, the numerator becomes denominator and
vice versa.

Example:

If two workers take 16 days to build 100m of fence, how many days will be spent using four workers?

Problem formulation.

2 workers - 16 days

4 workers - x days

Full text:**Rule of three - inverse proportion.**

**NOTE**: For this application, it is not necessary to replace the numerator by the denominator of the first ratio, because the program automatically performs the change.

Enter the requested data, according to the problem formulation, the results are automatically displayed after you click on **"Calculate"**

### Related topics

Percent of a number Percent of a total Accumulated total by a percentage Percentage of two numbers Arithmetic mean Geometric mean Harmonic mean Quadratic mean Weighted mean Weighted geometric mean Weighted harmonic mean Standard Deviation Correlation Coefficient Simple Linear Regression Quadratic equation Cubic equation solver Nth root solver Nth Power of a number Logarithm & antilogarithm solver Trigonometric Functions Inverse Trigonometric Functions Directly proportional division Inversely proportional division Determinant matix 3 by 3 Linear equations in two variables Linear equations in three variables Rule of three - direct proportion Rule of three - inverse proportion Compound Rule of three Restaurant - checking the bill