What is 7/4 of 45?

Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 7/4 of 45? We'll show you a straightforward method to achieve that.

How to calculate 7/4 of 45?

  1. Multiply the whole number by the numerator of the fraction: 45 × 7 = 315
  2. Divide this result by denominator of the fraction: 315/4 = 78.75

Since 315/4 is an improper fraction, the result could also be expressed as a mixed number: 78 3/4

How does it work?

The principle behind finding a fraction of a number, such as 7/4 of 45, is rooted in the method of cross-multiplication.

Consider the following proportion: 7 4 = x 45 (where x represents 7/4 of 45)

  1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: 7 × 45 = 4 x
  2. Which gives: 315 = 4 x
  3. Divide both sides by 4 to isolate x: 315 4 = 4 x 4
  4. Which gives the result: 315 4 = x

Thus, 7/4 of 45 is equal to 315/4 (or 78.75 in its decimal form).