3/4 as a percentage is 75.00%. This value tells you how much of a whole the fraction represents when you look at it in terms of hundredths.
In everyday language, saying something is 75.00% means three out of every four parts are present. It's a quick way to compare sizes without dealing with fractions.
When you see 75.00% on a chart or a report, you know it is the same as the fraction 3/4, just expressed in a format that is easy to read for most people.