28/48 expressed as a percentage is 58.33%. This tells you that the fraction is a little more than half of a whole.
If you reduce 28/48, you get 7/12, which is the same value in a simpler form. The size of this fraction stays the same, whether you write it as 7/12, 28/48, or 58.33%.
Knowing the percentage makes it easy to compare with other numbers, like test scores or discounts. It shows that something is just over half of the total amount.