The rule of three calculator is a math tool that lets you find an unknown value from two other known values using a simple ratio. This tool is useful in a variety of situations, from simple percentage calculations to more complex calculations involving multiple values.

A simple proportion is a mathematical comparison between two quantities, which describes how these quantities are related to each other. With the simple proportion in the rule of 3 you can discover unknown values.

For example, if you know that a bottle of soda costs R$ 3.00 and you want to know how much 5 bottles would cost, you can use simple proportion to find the total price

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## Simple 3 Rule Calculator

The calculator has three input fields: value 1, value 2, and value 3. The user enters two known values into the value 1 and value 2 fields and an unknown value into the value 3 field. When the user clicks the “Calculate” button , the calculator uses the simple rule of three formula to find the unknown value and displays the result in the output field.

## How does the rule of 3 calculator work?

The rule of three is used to solve a simple ratio between two values, and is expressed in the form:

value1 / value2 = value3 / x

Where “x” is the unknown value we are trying to find. To find the value of “x”, we can rearrange the formula as:

x = value2 * value3 / value1

The rule of three calculator uses this formula to calculate the unknown value entered by the user. The user needs to input the known values and click on the “Calculate” button to get the unknown value.

The calculator's interface is simple and intuitive, with input fields for known values and an output field for calculated unknown values. The result is displayed in numeric format with two decimal places, which is suitable for most calculations.

While the online rule of three calculator is a useful tool for solving simple proportions, it is important to remember that the rule of three is not appropriate for all types of math problems. More complex problems may require the use of other mathematical tools or a different approach to problem solving.

## When to use the Rule of 3?

The Rule of Three Calculator is an extremely useful math tool for solving simple proportions between two values. It can be used in many everyday situations, such as:

**Calculation of percentages:**For example, if you know that 20% of a quantity equals 100, you can use the rule of three to find out what the total value is. In this case, the known value would be 20% (or 0.2) and the unknown value would be the total value.**Unit conversion:**For example, if you know that 10 centimeters equals 4 inches, you can use the rule of three to convert centimeters to inches or vice versa. In this case, the known value would be 10 centimeters and the unknown value would be the equivalent in inches.**Calculation of proportions:**For example, if you know that 3 bottles of water cost R$ 15, you can use the rule of three to find out how much 5 bottles would cost. In this case, the known value would be 3 bottles for R$ 15 and the unknown value would be the cost of 5 bottles.**Solving direct and inverse proportionality problems:**For example, if you know that 6 workers can build a house in 12 days, you can use the rule of three to find out how many days it would take 12 workers to build the same house. In this case, the known value would be 6 workers for 12 days and the unknown value would be the number of days required for 12 workers.