Proportions only easy and fast

This app is made only for doing proportion, in the classic way: a: b = c:? If you don't know how it works or for what to use this app read below. Supports all proportion's formats like: a: b = c: x. A: b = x: c. X: b = c: d. A: x = c: d. Made it easy and fast, and with a cool graphic look.