Right, but in this case they only give you one of the two numbers. Imagine being told that your TV had an aspect ration of ":16", and you just have to magically know what the other number means in the context. And sometimes ":16" actually means ":4", because quadratic mumble mumble, and sometimes the number is scaled according to some other "how big it seems to humans" factor; all of which you also just have to know in context.