The square of a number other than $1$ is either a multiple of $3$ or exceeds a multiple of $3$ by . [Write the answer in numeral form]

Find the square root of the following using repeated subtraction.

$81$

Find the square root of the following using repeated subtraction.

$121$

Find the square root of the following using repeated subtraction.

$169$

Find the square root of the following using repeated subtraction.

$225$

Find the square root of the following using prime factorisation method.

$784$

Find the square root of the following using prime factorisation method.

$2304$

Find the square root of the following using prime factorisation method.

$1296$

Find the square root of the following using prime factorisation method.

$3969$