Rule of Three Calculator

Type of rule of three

If 3 kg cost €12, then 5 kg cost X.

A: known quantityB: its matching valueC: the new quantity

X: the result

How the result is reached

3 is to 12 as 5 is to X · X = B × C ÷ A = 20

Educational arithmetic tool. The result is an exact proportion between the values entered.