Check sibling questions

Let’s do this by examples

 

Is 216 a perfect cube?

Let’s do prime factorization of 216

Thus,

 216  = 2 × 2 × 2 × 3 × 3 × 3

 

Now,

We make groups of 3

Since 2 & 3 occur in triplets.

∴ 216 is a perfect cube.

 

Cube root of 216 = 2 × 3

         = 6

 

Is 729 a perfect cube?

Doing Prime factorization of 729

We see that

 

Since 3 occurs in triplets.

∴ 729 is a perfect cube.

 

Cube root of 729 = 3 × 3

 

Is 3375 a perfect cube?

Doing Prime factorization of 3375

We see that

Since 3 & 5 occurs in triplets.

∴ 3375 is a perfect cube.

 

Cube root of 3375 = 3 × 5

       = 15

 

Is 1125 a perfect cube?

Doing Prime factorization of 1125

We see that

Since 3 does not occur in triplets

∴ 1125 is not a perfect cube.

 

Is 6859 a perfect cube?

Doing Prime factorization of 6859

We see that

Since 19 occurs in triplets.

∴ 6859 is a perfect cube.

 

Cube root of 6859 = 19

 

Is 10648 a perfect cube?

Doing Prime factorization of 10648

We see that

Since 2 & 11 occurs in triplets.

∴ 10648 is a perfect cube.

 

Cube root of 10648 = 2 × 11

        = 22

 

Is 5324 a perfect cube?

Doing Prime factorization of 5324

We see that

Since 2 does not occur in triplets.

∴ 5324 is not a perfect cube.

 

Is 968 a perfect cube?

Doing Prime factorization of 968

We see that

Since 11 does not occur in triplets.

∴ 968 is not a perfect cube

 

Is 400 a perfect cube?

Doing Prime factorization of 400

Since 2 & 5 do not occur in triplets.

∴ 400 is not a perfect cube.

  1. Chapter 6 Class 8 Cubes and Cube Roots
  2. Concept wise

About the Author

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo