The fraction 12/58 expressed as a percentage is 20.69%. This value tells you how much of a whole the fraction represents when you look at it in terms of hundred parts.
In everyday situations, you might see this percentage used to compare parts of a group, such as the share of a class that prefers a certain snack. The original fraction can also be reduced to 6/29, but the percentage stays the same, giving a quick visual sense of size.
Remember that percentages are handy for making comparisons because most people think in terms of “out of 100.” So whenever you need to communicate the size of 12/58, saying 20.69% is clear, concise, and easy to understand.