34/76 as a percentage is 44.74%. This number tells you how much of a whole the fraction represents when you look at it in a familiar “out of 100” format.
The fraction 34/76 can be reduced to 17/38, which still points to the same part of a whole. Even though the numbers look different, the value stays the same, so the percentage stays 44.74%.
Knowing the percentage makes it easier to compare this part with other percentages, like a test score or a discount. It’s a quick way to see that the fraction is a little less than half of the whole.