Yes,. The use of ratios is necessary in most situations.
Yes, they are.
Yes.
Ratios are very important part of mathematics. They teach us how to deal with proportions.
Some important jobs would be farming, building, merchants, fur trading, etc.
acting farming trapping hunting
Jo mamma
Ratios are imperative in cooking. This is due to making the proper balance of ingredients that won't throw the recipe off.
Some of the infinitely many ratios are 130/10, 1300/100.
This question is subjective. They're all important in different ways. You can view the different Canadian Air Force jobs at the related link below.
They do combine in whole number ratios, but these ratios need not be simple - particularly in some organic compounds.
Ratios are used in biology, astronomy and math. Most every science where comparisons are made (and that is just about every science) requires a good understanding of ratios. They are particularly important in medicine, in mixing dosages.