Question

Find the square root of:

(1) 441

Answer 1

Prime factorisation of 441:

$\begin{array}{cc}3& 441\\ 3& 147\\ 7& 49\\ 7& 7\\ & 1\end{array}$

= 3 × 3 × 7 × 7
= (3 × 7)²

∴ Square root of 441 = 3 × 7 = 21