RBSE Solutions for Class 8 Maths Chapter 2 Cube and Cube Roots Ex 2.2 is part of RBSE Solutions for Class 8 Maths. Here we have given Rajasthan Board RBSE Class 8 Maths Chapter 2 Cube and Cube Roots Exercise 2.2.

Board |
RBSE |

Textbook |
SIERT, Rajasthan |

Class |
Class 8 |

Subject |
Maths |

Chapter |
Chapter 2 |

Chapter Name |
Cube and Cube Roots |

Exercise |
Exercise 2.2 |

Number of Questions |
2 |

Category |
RBSE Solutions |

## Rajasthan Board RBSE Class 8 Maths Chapter 2 Cube and Cube Roots Ex 2.2

Question 1.

Determine True/False in the given statements.

(i) Every even number(RBSESolutions.com)has even cube.

(ii) A perfect cube does not end with double zero (00).

(iii) No one perfect cube end with 8.

(iv) If square of any number is ending with 5 then its cube is end with 25.

(v) Cube of single digit is also a single digits number.

(vi) Cube of double(RBSESolutions.com)digit number is of 4 to 6 digits.

Solution.

(i) True

(ii) True

(iii) False

(iv) True

(v) False

(vi) True

Question 2.

Find the cube roots of the following numbers by estimate(RBSESolutions.com)and prime factor method. Verify your answer

(i) 64

(ii) 343

(iii) 5832

(iv) 74088

(v) 3375

(vi) 10648

(vii) 46656

(viii) 91125

Solution.

Prime Factorization method

(i) Resolving 64 into Prime factors as follows :

Step I Make groups of three digits, starting from unit place digit as 064

Step II. 1st group is 64. Its unit(RBSESolutions.com)digit is 4 which is obtained only by the cube of a number whose unit digit is 4 (4³ = 64)

Therefore, cube root of 64 is 4.

(ii) Resolving 343 into Prime factors as follows :

Step I. Make group of three digits, starting from unit place digit as 343

Step II. First group is 343. Its(RBSESolutions.com)unit digit is 3 which is obtained only by the cube of a number whose unit digit is 7

(7³ = 343)

∴ Cube root of 343 is 7

(iii) Resolving 5832 into Prime factors as follows :

Step I. Make groups of three digits starting from unit place(RBSESolutions.com)digits as __5__ __832__

Step II. 1st group is 832 and its unit place digit is 2 which is obtained only by the cube a number whose unit digit is 8

(8³ = 512)

So, we get 8 at the unit place digit of the cube root.

Step III. Second group is 5 which is(RBSESolutions.com)greater than cube of 1 and smaller than cube of 2

∴ 1³<5<2³

Therefore, tens place digit is 1 .

Therefore, Cube root of ³√5832 = 18

(iv) Resolving 74088 into Prime factors as follows :

Step I. Make groups of three digits starting from unit place digit as __77__ __088__

Step II. 1st group is 088, its unit digit 8 which is obtained by the cube of 2 i.e. (2³ = 8)

∴ We get 2 at the(RBSESolutions.com)unit places digit of the cube root.

Step III. IInd group is 74

Therefore, 4³ < 74 < 5³

∴ Ten place digit is 4

Therefore. ³√74088 = 42

(v) Resolving 3375 into Prime factors as follows :

Step I. Make groups of three digits, starting from unit place digit as __3__ __375__.

Step II. 1st group is 375 Its unit place digit is 5 which is obtained only by the cube of any number having unit place digit 5

(5³ = 125)

So we get 5 at the unit’s place(RBSESolutions.com)of the cube root.

Step III. IInd group is 3

Which is 1³ < 3 < 2³

Therefore, tens place digit is 1

∴ ³√3375 = 15

(vi) Resolving 10648 into Prime factors as follows :

Step I. Make groups of three digits, starting from unit place digit as __10__ __648__

Step II. 1st group is 648 Its unit place digit is 8 which can be obtained only by the cube of number having unit place digit as 2

(2³ = 8)

Therefore, we get 2 at the unit place digit of the cube root.

Step III. Second(RBSESolutions.com)group is 10

2³ < 10 < 3³

∴ Tens place digit is 2

Therefore, ³√10648 = 22

(vii) Resolving 46656 into Prime factors as follows :

Step I. Make groups of three digits starting from unit place digit as __46__ __656__

Step II. 1st group is 656. Its unit place digit is 6 which is obtained by the cube of any number having unit place digit as 6.

We know that 6³ = 216

Step III. Second(RBSESolutions.com)group is 46

3³<46<4³

∴ Ten place digit is 3

Hence, cube root of 46656 is 36

∴³√46656 = 36

(viii) Resolving 91125 into Prime factors as follows :

Step I. Make digit of three digits, starting from unit place digit __91__ __125__

Step II. 1st group is 125. Its unit place digit is 5 which is obtained only by the cube of any number having unit place digit as 5

(5³ = 125)

Step II. IInd group is 91

Here 4³<91<5³

Therefore,tens(RBSESolutions.com)place digit is 4

Therefore, ³√91125 = 45

We hope the given RBSE Solutions for Class 8 Maths Chapter 2 Cube and Cube Roots Ex 2.2 will help you. If you have any query regarding Rajasthan Board RBSE Class 8 Maths Chapter 2 Cube and Cube Roots Exercise 2.2, drop a comment below and we will get back to you at the earliest.

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