45.45% is what you get when you change the fraction 40⁄88 into a percentage.
The fraction 40⁄88 can be reduced to 5⁄11, which shows the same size in a simpler form. Both fractions represent a little less than one half of a whole.
Seeing it as 45.45% makes it easy to compare with other percentages, like sales tax or test scores, without having to work with the original numbers. This rounded figure is clear and useful for everyday calculations.