Example Square Roots: The 2nd root of 81, or 81 radical 2, or the square root of 81 is written as 81 2 = 81 = ± 9 . The 2nd root of 25, or 25 radical 2, or the square root of 25 is written as 25 2 = 25 = ± 5 . The 2nd root of 100, or 100 radical 2, or the square root of 100 is written as 100 2 = 100 = ± 10 .
