irrational number

Also found in: Thesaurus, Encyclopedia, Wikipedia.
Related to irrational number: imaginary number

irrational number

A real number that cannot be expressed as a ratio between two integers.

irrational number

(Mathematics) any real number that cannot be expressed as the ratio of two integers, such as π

irra′tional num′ber

a number that cannot be exactly expressed as a ratio of two integers.

ir·ra·tion·al number

A real number that cannot be expressed as a ratio between two integers. If written in decimal notation, an irrational number would have an infinite number of digits to the right of the decimal point, without repetition. Pi and the square root of 2 (√2) are irrational numbers.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.irrational number - a real number that cannot be expressed as a rational number
real, real number - any rational or irrational number
transcendental number - an irrational number that is not algebraic
algebraic number - root of an algebraic equation with rational coefficients
iracionalni broj
óræð tala
References in periodicals archive ?
Your students may not have met the irrational number [square root of (2)] in their mathematics courses at this stage, but here is a good place to start.
A few examples of the diverse topics covered in the volumes include acorn worm, air masses and fronts, animal cancer tests, big bang theory, biophysics, buckwheat, cardiac cycle, dentrification, dragonflies, geotropism, ice age refuges, irrational number, legumes, nuclear winter, oscillations, photocopying, quantum electrodynamics, restoration ecology, set theory, squirrel fish, tartaric acid, tumbleweed, ultraviolet astronomy, weather forecasting, xylotomy, and zodiacal light.
And, what irrational number is equal to a circle's circumference divided by its diameter?
A pendant has been manufactured based on the irrational number of Phi, also referred to as the Golden Ratio.
Since then, this never-ending, never-repeating, irrational number has been called the Golden Number or the Golden Ratio and linked to patterns ranging from the petal arrangement of roses to the composition of the "Mona Lisa.
Mathematicians have long known that pi is an irrational number.
Pi, the ratio of a circle's circumference to its diameter, is known as an irrational number because it can't be exactly expressed as a ratio of two whole numbers.
We didn't want to set another irrational number," he says.
Mathematicians, for instance, provedlong ago that pi is an irrational number.
Instead, the irrational number, (1 + [square root of] 5)/2, pervades the pattern.
Given the prolific use of calculators which present [pi] as an apparently terminating decimal (rather than as a rational number approximation), the notion of [pi] as an irrational number is probably not emphasised nor even paid attention to in many classrooms.
They realised that [empty set] was an irrational number and embodied it in the pentagram, which they used as their secret sign.