The square root of a number is one of two equal factors of that number.
For example, 13 × 13 = 169 and 13 is one of the two equal factors of 169. Therefore, 13 is the square root of 169.
The square root of 100 is 10 because 10 × 10 = 100
The square root of 121 is 11 because 11 × 11 = 121
The square root of 225 is 15 because 15 × 15 = 225
The square root of 361 is 19 because 19 × 19 = 361
The square root of 625 is 25 because 25 × 25 = 625
The square root of a number can also be a negative number.
For example, the square root of 100 could also be -10 because -10 × -10 = 100
The square root of 121 could also be -11 because -11 × -11 = 121
The square root can also be a real number.
For example, the square root of 250 is 15.81 or -15.81 since 15.81 × 15.81 is closely equal to 250 and -15.81 × -15.81 is closely equal to 250.