Square root of 2
unique positive real number which when multiplied by itself gives 2 / From Wikipedia, the free encyclopedia
The square root of 2, or the (1/2)th power of 2, written in mathematics as √2 or 21⁄2, is the positive irrational number that, when multiplied by itself, equals the number 2.[1] To be more correct, it is called the principal square root of 2, to tell it apart from the negative version of itself where that is also true.
Geometrically, the square root of 2 is the length of a diagonal across a square with sides with a length of one; this can be found with the Pythagorean theorem. Because of that, it is also called the Pythagoras's constant.[2]