What is 5/9 of 72?
Often, in mathematics or everyday life, we need to find a fraction of a given number. For instance, how would you quickly calculate 5/9 of 72? We'll show you a straightforward method to achieve that.
How to calculate 5/9 of 72?
- Multiply the whole number by the numerator of the fraction: 72 × 5 = 360
- Divide this result by denominator of the fraction: 360/9 = 40
- Simplify by dividing both the numerator and denominator by their GCD (9):
- 360/9 = 40
- 9/9 = 1
- Which gives: 40/1
How does it work?
The principle behind finding a fraction of a number, such as 5/9 of 72, is rooted in the method of cross-multiplication.
Consider the following proportion: (where x represents 5/9 of 72)
- Using the cross-multiplication method, multiply both numerators by their opposite denominators:
- Which gives:
- Divide both sides by 9 to isolate x:
- Which gives the result: (or )
Thus, 5/9 of 72 is equal to 40/1 (or 40 in its decimal form).