Question

How many times the number 3 should be mutiplied with 648, in order to make it a perfect cube?

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Answer 1

$\begin{array}{cc}2& 648\\ 2& 324\\ 2& 162\\ 9& 81\\ & 9\end{array}$

Prime factors of 648 = 2 $\times$ 2 $\times$ 2 $\times$ 3 $\times$ 3 $\times$ 3 $\times$ 3
The power on 3 is 4, so it is not a perfect cube.
Hence, 3 should be multiplied twice with 648, in order to make it a perfect cube.