Find the square root by long division method. $400$

Find the square root by long division method. $1764$

Find the square root of $9801$ by long division method. $$

Without calculating the square root, guess the number of digits in the square root of $14400$.

Without calculating the square root, guess the number of digits in the square root of $390625$.

Without calculating the square root, guess the number of digits in the square root of $100000000$.