What is 4/5 of 89?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 4/5 of 89? We'll show you a straightforward method to achieve that.

How to calculate 4/5 of 89?

  1. Multiply the whole number by the numerator of the fraction: 89 × 4 = 356
  2. Divide this result by denominator of the fraction: 356/5 = 71.2

Since 356/5 is an improper fraction, the result could also be expressed as a mixed number: 71 1/5

How does it work?

The principle behind finding a fraction of a number, such as 4/5 of 89, is rooted in the method of cross-multiplication.

Consider the following proportion: 4 5 = x 89 (where x represents 4/5 of 89)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 4 × 89 = 5 x
  2. Which gives: 356 = 5 x
  3. Divide both sides by 5 to isolate x: 356 5 = 5 x 5
  4. Which gives the result: 356 5 = x

Thus, 4/5 of 89 is equal to 356/5 (or 71.2 in its decimal form).