What Is a Square Root?

The square root of a number is the non-negative number whose square is that number, written with the √ sign. Since 14² = 196, √196 = 14. Negative numbers have no real square root. The root of a whole number that is not a perfect square simplifies to a√b: √72 = 6√2.

Where it appears in the formulas

√x = a × √b, where a² × b = x. For √72 the square root calculator shows the step √(6² × 2) = 6 × √2 and gives the root as about 8.485.