Meaning & use
irrational number
A real number that cannot be expressed exactly as a ratio of two whole numbers, such as pi or the square root of two.
See it in a sentence
The square root of two is an irrational number because its decimal expansion never repeats or ends.
Pi is perhaps the most famous irrational number used in geometry and trigonometry.
A note on using this word
An irrational number's decimal representation continues forever without repeating, unlike a rational number.
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