Find the number of digits in the square root of each of the following numbers: (i) 64 (ii) 144 (iii) 4489 (iv) 27225 (v) 390625

If the number of digits of a number is even, then its square root will have half (whole number) of the number of digits. If the number of digits of a number are odd, then its square root will have half (nearest greater whole number) of the number of digits.
i) √64
The number of digits is 2 i.e., even. Therefore, there is only 1 digit in the square root of 64.
ii) √144
The number of digits is 3 i.e., odd. Therefore, there are (1.5 =) 2 digits in the square root of 144.
iii) √4489
The number of digits is 4 i.e., even. Therefore, there are 2 digits in the square root of 4489.
iv) √27225
The number of digits is 5 i.e., odd. Therefore, there are (2.5=) 3 digits in the square root of 27225.
v) √390625
The number of digits is 6 i.e., even. Therefore, there are 3 digits in the square root of 390625.