# User Contributed Dictionary

### Noun

ratios- Plural of ratio

# Extensive Definition

A ratio is a quantity that denotes the
proportional
amount or magnitude of one quantity relative to another.

Ratios are unitless when they relate
quantities of the same dimension. When the two
quantities being compared are of different types, the units are the
first quantity "per" unit of the second — for example, a
speed or velocity can
be expressed in "miles per hour". If the second unit is a measure
of time, we call this type of ratio a rate.

Fractions
and percentages are
both specific applications of ratios. Fractions relate the part
(the numerator) to the whole (the denominator) while percentages
indicate parts per 100.

A ratio of 2:3 ("two to three") means that the
whole is made up of 2 parts of one thing and 3 parts of another
— thus, the whole contains five parts in all. To be
specific, if a basket contains 2 apples and 3 oranges, then the
ratio of apples to oranges is 2:3. If another 2 apples and 3
oranges are added to the basket, then it will contain 4 apples and
6 oranges, resulting in a ratio of 4:6, which is equivalent to a
ratio of 2:3 (thus ratios reduce
like regular fractions). In this case, 2/5 or 40% of the fruit are
apples and 3/5 or 60% are oranges in the basket.

Note that in the previous example the proportion
of apples in the basket is 2/5 ("two of five" fruits, "two out of
five" fruits, "two fifths" of the fruits, or 40% of the fruits).
Thus a proportion compares part to whole instead of part to
part.

Throughout the physical
sciences, ratios of physical quantities are treated as real numbers.
For example, the ratio of 2 \pi metres to 1 metre (say, the ratio
of the circumference of a certain circle to its radius) is the real
number 2 \pi. That is, 2 \pim/1m = 2 \pi. Accordingly, the
classical definition of measurement is the
estimation of a ratio between a quantity and a unit of the same
kind of quantity. (See also the article on
commensurability in mathematics.)

In algebra, two quantities having a
constant ratio are in a
special kind of linear
relationship called
proportionality.

ratios in Catalan: Raó aritmètica

ratios in Danish: Forhold

ratios in Estonian: Jagatis

ratios in Modern Greek (1453-):
Αριθμοδείκτης

ratios in Spanish: Razón aritmética

ratios in Esperanto: Rilatumo

ratios in Korean: 비 (수학)

ratios in Italian: Rapporto

ratios in Hebrew: יחס (בין מספרים)

ratios in Lithuanian: Santykis

ratios in Dutch: Verhouding (wiskunde)

ratios in Japanese: 比

ratios in Polish: Stosunek (matematyka)

ratios in Portuguese: Taxa (razão)

ratios in Simple English: Ratio

ratios in Serbian: Рацио

ratios in Telugu: నిష్పత్తి

ratios in Thai: อัตราส่วน