What is a 4:1 ratio? Is it equivalent to 75% to 25%?

Ratios are basically:

for this much of this:theres this much of that

lets say you have 4:1 in spoons and forks.

for every 4 spoons, there is 1 fork. if there is 8 spoons there are 2 forks and so on.

The percent is 400%

if you meant 1:4 the percent would be 25%. all other rules apply.

for every 1 spoon you have 4 forks.