55/84 as a percentage is 65.48%. This number tells you how much of a whole 55 parts out of 84 represent when you look at it on a scale of 100.
The fraction 55/84 can be simplified only a little, because 55 and 84 share no common factors other than 1. It sits between 1/2 (which is 50%) and 3/4 (which is 75%), making it a useful middle value in many everyday calculations.
When you see 65.48% on a chart or report, you know it comes from the same ratio as 55/84. That makes it easy to compare with other percentages, like a test score of 70% or a discount of 60%.
Understanding both the fraction and its percentage version helps you move quickly between exact ratios and the more familiar “out of 100” format that we see in most everyday contexts.