irrational number

noun

Definition of irrational number

: a number that can be expressed as an infinite decimal with no set of consecutive digits repeating itself indefinitely and that cannot be expressed as the quotient of two integers

Examples of irrational number in a Sentence

Recent Examples on the Web

But no matter how fine the grid, the ninth dot always falls between grid points; it is forced to correspond to an irrational number. Quanta Magazine, "Visions of Future Physics," 22 Sep. 2015 But to the brothers’ dismay Hippasus proved that the side of a square has no common measure with its diagonal, and consequently some magnitudes—known as irrational numbers—cannot... Amir Alexander, WSJ, "‘The Universe Speaks in Numbers’ Review: The Inner Observatory," 7 June 2019 An irrational number is one that cannot be expressed by a fraction of integers, or whole numbers. Jay Bennett, Popular Mechanics, "The Mysteries of the Golden Ratio Explained by Math and Sunflowers," 11 May 2018 The short way to say this is that pi is an irrational number, one that cannot be represented as a fraction and thus has an infinite and never-repeating decimal expansion. Dan Rockmore /, NBC News, "Pi Day spotlights one of math's most seductive numbers," 14 Mar. 2018 This distinguishes it again from more familiar irrational numbers like the square root of two (whose second power is equal to two). Dan Rockmore /, NBC News, "Pi Day spotlights one of math's most seductive numbers," 14 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'irrational number.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of irrational number

1551, in the meaning defined above

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Last Updated

1 Jul 2019

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The first known use of irrational number was in 1551

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More from Merriam-Webster on irrational number

Britannica.com: Encyclopedia article about irrational number

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