Question

Find the smallest number by which the following number must be divided to obtain a perfect cube.

81

Answer 1

3	81
3	27
3	9
3	3
	1

81 = 3 × 3 × 3 × 3

Here, one 3 is left, which is not in a triplet.

If we divide 81 by 3, then it will become a perfect cube.

Thus, 81 ÷ 3

= 27

= 3 × 3 × 3 is a perfect cube.

Hence, the smallest number by which 81 should be divided to make it a perfect cube is 3.