Drinking 8 fluid ounces of milk provides 270.0 milligrams of calcium. How many fluid ounces of milk provide 72.5 milligrams of calcium? Round to the nearest tenth.

I believe this is a problem dealing with proportions, so you could cross multiply and divide. so you would do 8/270 then x/72.5, you cross multiply 72.5x8 which equals 580. then you divide that answer by 100 which equals 5.8