13/74 as a percentage is 17.57%. This number tells you how much of a whole 13 parts out of 74 represent when the whole is considered as 100 %.
In everyday terms, if you had 74 equal slices of a pizza and ate 13 of them, you would have eaten about 17.57 % of the pizza.
Seeing a percentage like this helps compare fractions to other values that are already in percent form, such as discounts or test scores.
So whenever you need a quick sense of size, remember that 13/74 is roughly 17.57% of the total.