How is a percent expressed?

A percent is actually defined as a way to express a number as a fraction of 100. The term "percent" literally means "per hundred," which indicates that it is a ratio comparing a given quantity to 100. For example, when saying 25%, you are indicating that there are 25 parts out of 100 parts.

Understanding this relationship helps clarify why percent is fundamentally tied to the number 100, and this is a key reason that option describing the ratio comparing to 100 is the most accurate representation of how a percent is expressed. Expressing a percent as a fraction, decimal, or whole number can be correct in certain contexts, but they ultimately can all be converted back to the fundamental definition rooted in the concept of "per hundred."