Question

By what least number should 648 be multiplied to get a perfect cube?
(a) 3 (b) 6
(c) 9 (d) 8

Answer 1

Factorising 648, we get
$648=2\times 2\times 2\times 3\times 3\times 3\times 3=2^3\times 3^3\times 3$
$\therefore$ In order to get a perfect cube, we have to multiplyh by $3\times 3$ to complete the triplet
Required number = 9