78 divided by 90 expressed as a percentage is 86.67%. This number tells you how much of a whole the fraction represents when the whole is taken as 100%.
The fraction 78/90 can also be reduced to 13/15, which is still the same part of a whole. Whether you write it as a fraction, a decimal, or a percentage, the value stays the same.
In everyday use, percentages are often easier to understand than fractions. So when you see 86.67%, you know that 78 out of 90 items are present, or that something is about 87% complete.
