Irrational numbers

In mathematics, an irrational number is any real number that cannot be expressed as a ratio of integers.



The number   is irrational.

Numbers which are irrational include the ratio π of a circle's circumference to its diameter, Euler's number e, the golden ratio φ, and the square root of two. 

All square roots of natural numbers, other than of perfect squares, are irrational.

Source adapted from Irrational number. (2015, August 26). In Wikipedia, The Free Encyclopedia. Retrieved 10:31, August 26, 2015, from