Question

Question 3(i)
Find the smallest number by which each of the following numbers must be divided to obtain a perfect cube:
81

Answer 1

81
Prime factors of $81=3\times 3\times 3\times 3$
Here one factor 3 is not grouped in triplets.
Therefore 81 must be divided by 3 to make it a perfect cube.
$\begin{array}{cc}3& 81\\ 3& 27\\ 3& 9\\ 3& 3\\ & 1\end{array}$