12/58 as a percentage is 20.69%. This rounded figure gives a quick sense of how large the fraction is compared to a whole.
The fraction 12/58 can also be reduced to 6/29, which still represents the same value. Whether you keep it as 12/58 or 6/29, the proportion stays the same, and the percentage stays at 20.69%.
In everyday situations, you might see this kind of number when looking at test scores, survey results, or any data that breaks a whole into parts. Knowing the percentage helps you compare it easily with other values that are already expressed in percent.
