Ratio Master app for iPhone and iPad

Do you keep yourself awake at night trying to figure out math ratio questions like "what is X, if (5/7) = (9/X)?" Are you racking your brains trying to figure things out like "if I paid $42 for this with tax, how much was the tax rate if the item by itself was $39?", but have no idea how to plug something like that into the calculator? Think theres no answer? Youre so stupid! Of course there is!

Introducing Ratio Master: the hottest new way to calculate your annoying ratio problems. Thinking with your head is so early 1900s. Using traditional calculators for specific problems like this is for savages. Get with the times and calculate your ratios with style!