These are formulas that will never change. There is absolutely no issues to hard-code such algorithms. Adding unessary variables will just make your code more complex without giving any benefits. However, DRY code is just as important so if you are finding yourself writing this ratio over and over in many places, it could then be a good idea to store it in a variable. For instance, if I had to use the number 666 at many places in my code, even if that number would never ever change, I would say it's better to define it as a constant since it's less error-prone.
final int NUMBER_OF_THE_BEAST = 666;