What is 3/7 of 30?

How to calculate 3/7 of 30?

1. Multiply the whole number by the numerator of the fraction: 30 × 3 = 90
2. Divide this result by denominator of the fraction: 90/7 = 12.857142857143

Since 90/7 is an improper fraction, the result could also be expressed as a mixed number: 12 6/7

How does it work?

The principle behind finding a fraction of a number, such as 3/7 of 30, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{3}{7}=\frac{x}{30}$ (where x represents 3/7 of 30)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $3\times 30=7x$
2. Which gives: $90=7x$
3. Divide both sides by 7 to isolate x: $\frac{90}{7}=\frac{7x}{7}$
4. Which gives the result: $\frac{90}{7}=x$

Thus, 3/7 of 30 is equal to 90/7 (or 12.857142857143 in its decimal form).