What is 1/8 of 90?

How to calculate 1/8 of 90?

1. Multiply the whole number by the numerator of the fraction: 90 × 1 = 90
2. Divide this result by denominator of the fraction: 90/8 = 11.25
3. Simplify by dividing both the numerator and denominator by their GCD (2):
   • 90/2 = 45
   • 8/2 = 4
4. Which gives: 45/4

Since 45/4 is an improper fraction, the result could also be expressed as a mixed number: 11 1/4

How does it work?

The principle behind finding a fraction of a number, such as 1/8 of 90, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{1}{8}=\frac{x}{90}$ (where x represents 1/8 of 90)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $1\times 90=8x$
2. Which gives: $90=8x$
3. Divide both sides by 8 to isolate x: $\frac{90}{8}=\frac{8x}{8}$
4. Which gives the result: $\frac{90}{8}=x$ (or $\frac{45}{4}=x$)

Thus, 1/8 of 90 is equal to 45/4 (or 11.25 in its decimal form).