4.125 is a fraction. It is a fraction in decimal form rather than in the form of a ratio. However, that does not stop it being a fraction. Its equivalent, in rational form, is 4125/1000. You can simplify this rational fraction if required.
0.4125 as a fraction is 4125/10000.
5/4125%= 125/100 or 5/4 in fraction
4.125 as a fraction is: 4125/1000 = 33/8 = 41/8
56.4 converted in to a fraction is 273/5.
8.5% converted to a fraction in lowest terms is 17/200