Question

Find the cube root of 91125 by prime factorisation method.

Answer 1

Factorsing 91125 using the prime factorisation method,

$\begin{array}{cc}3& 91125\\ 3& 30375\\ 3& 10125\\ 3& 3375\\ 3& 1125\\ 3& 375\\ 5& 125\\ 5& 25\\ 5& 5\\ & 1\end{array}$

$\sqrt[3]{391125}=\sqrt[3]{33\times 3\times 3\times 3\times 3\times 3\times 5\times 5\times 5}=3\times 3\times 5=45$