17/90 as a percentage is 18.89%. This fraction is a little less than one fifth, so its decimal and percent values are both under 20 %. Knowing the rounded percent makes it easy to compare with other numbers in everyday situations.
The fraction 17/90 can show up in simple surveys or school projects where you count 17 items out of a total of 90. Expressing it as 18.89% lets you quickly see the share of the whole without having to work with a weird looking fraction.
When you round to two decimal places, the percent stays clear and useful. The tiny difference between 18.88% and 18.90% is usually not important for most practical uses, so 18.89% is a convenient and accurate way to describe the portion that 17 out of 90 represents.
