Rule of Three - Calculator

My Rule of Three is a simple but very useful calculator when you need to calculate ratios which are proportional to each other, for both modes direct and inverse proportional.
For a better understanding we have this example:
For traveling 250 Km a car needs 18.50 litres of petrol and we want to know how many litres of petrol the car will need for traveling 475 Km ... ?
Then we have the next known values that we can use for calculating the unknown one, in our case "x":
a = 250 Km -----> b = 18.50 litres
c = 475 Km -----> x = ?
We also know that the calculation mode has to be direct mode because the values are directly proportional to each other, (the larger distance the car will travel the more petrol it will consume).
All we have to do is filling in the known values into their corresponding fields, selecting "Direct mode" and press the "CALCULATE" button, the result will be shown in the result field.
In this way we can use My Rule of Three calculator for calculating the unknown value that in this case will be 35.15 litres.
The application can also save up to 100 calculations in its history memory including all the values, if they might be needed for a later use.
I hope you will find this application useful and enjoy it ... !!!