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### Ratio

A ratio shows the relationship between two quantities. You write it often with a colon as

a : b

and you call it the quotient of a and b.

##### Explanation

In general you can write

 numerator = dividend = quotient = fraction = ratio denominator divisor

##### Example 1

Ratios can be calculated by cross-multiplication

a : b = c : d

gives then

a × d = b × c

##### Example 2

Two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities where a > b > 0.

##### Example 3

The number π = 3.1415… describes the ratio between the circumference and the diameter of a circle

 π = circumference diameter

en kan door geen enkel paar gehele getallen worden weergegeven. It is a transcendental number.

##### Example 4

The number √2 = 1,4142... is the ratio between the side and the diameter of a square, and cannot be written by any pair of whole numbers. It is an irrational number.

##### Example 5

A probability is the ratio between the number of favorable outcomes and the number of possible outcomes

 P(G) = number of favorable outcomes number of possible outcomes