21/45 as a percentage is 46.67%. This value tells you how much of a whole 21 parts out of 45 represent when you think in terms of 100.
The fraction 21/45 can be simplified to 7/15, which still keeps the same proportion. Whether you write it as a fraction or a percent, the relationship between the two numbers stays the same.
Percentages like 46.67% are useful in everyday situations—such as figuring out test scores, discounts, or survey results—because they let you compare parts of a whole quickly and easily.
