. Which of the following are not perfect cubes


(i) 216 (ii) 128 (iii) 1000 (iv) 100 (v) 46656

Best Answer

Explanation:

(i) 216

Prime factorisation is 2x2x2x3x3x3

Here, two pairs are formed 23x33.

So, 216 is a perfect cube.

(ii) 128

Prime factorisation is 2x2x2x2x2x2x2

Two pairs of 23x23 is formed and one factor 2 is remaining.

 It is not a perfect cube.

(iii) 1000

Prime factorisation is 10x10x10

one pair of 103 is formed.

 It is a perfect cube.

(iv) 100

Prime factorisation is 10x10

There are no pair of three.

It is not a perfect cube.

(v) 46656

Prime factorisation of is 2x2x2x2x2x2x3x3x3x3x3x3

4 pairs of 23x23x33x33 are formed.

It is a perfect cube.

Final Answer:

Hence, 128 and 100 are not perfect cubes.

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