How it is calculated
The cross-products are equal: a × x = b × c. From that, x = b × c / a. If a different slot is the unknown, rearrange the numbers so the empty slot is x.
x = b × c / a
Where the numbers come from
- a — Left numerator.
- b — Left denominator.
- c — The right-hand numerator. x is in the denominator.
Example
2 / 4 = 3 / x. Then x = 4 × 3 / 2 = 6.
Questions
How do I solve a / x = c / d?
Rewrite it as c / d = a / x, and set field a to c, field b to d, and field c to a from the original line.
Can it be zero?
Division by a = 0 is not allowed. A zero in the other fields gives x = 0, when that makes sense for the problem.
Are percentages calculated here?
A share is easier to read in the percent calculator. A proportion stays a relation among four numbers.