What is the square root of 2?

The square root of 2 is approximately 1.41. Like all square roots of nonperfect square numbers, the square root of 2 is an irrational number, so the decimal never ends and never falls into a repeating pattern.

According to the Pythagorean formula, a right isosceles triangle with both legs equal to 1 has a hypotenuse equal to the square root of 2. This relationship is so important that the square root of 2, sometimes called root 2, is known as Pythagoras' constant. For all right isosceles triangles, the relationship between the sides follows the pattern of 1:1:root 2. For example, a right isosceles triangle with legs equal to 10 has a hypotenuse of 10 root 2.