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R.D. Sharma solutions for Mathematics [English] Class 8 chapter 4 - Cubes and Cube Roots [Latest edition]

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R.D. Sharma solutions for Mathematics [English] Class 8 chapter 4 - Cubes and Cube Roots - Shaalaa.com
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Solutions for Chapter 4: Cubes and Cube Roots

Below listed, you can find solutions for Chapter 4 of CBSE R.D. Sharma for Mathematics [English] Class 8.


Exercise 4.1Exercise 4.2Exercise 4.3Exercise 4.4Exercise 4.5
Exercise 4.1 [Pages 7 - 9]

R.D. Sharma solutions for Mathematics [English] Class 8 4 Cubes and Cube Roots Exercise 4.1 [Pages 7 - 9]

1.1Page 7

Find the  cubes of the number  7 .

1.2Page 7

Find the  cubes of the number 12 .

1.3Page 7

Find the  cubes of the number 16 .

1.4Page 7

Find the  cubes of the number 21 .

1.5Page 7

Find the  cubes of the number 40 . 

1.6Page 7

Find the  cubes of the number 55 .

1.7Page 7

Find the  cubes of the number 100 . 

1.8Page 7

Find the  cubes of the number 302 .

1.9Page 7

Find the  cubes of the number 301 .

2Page 8

Write the cubes of all natural numbers between 1 and 10 and verify the following statements:
(i) Cubes of all odd natural numbers are odd.
(ii) Cubes of all even natural numbers are even.

2.1Page 47

Find if the following number is not a perfect cube? 

243

3Page 8

Observe the following pattern:
                13 = 1
        13 + 23 = (1 + 2)2
13 + 23 + 33 = (1 + 2 + 3)2
Write the next three rows and calculate the value of 13 + 2+ 33 + ... + 9+ 103 by the above pattern.

4Page 8

Write the cubes of 5 natural numbers which are multiples of 3 and verify the followings:
'The cube of a natural number which is a multiple of 3 is a multiple of 27'

5Page 8

Write the cubes of 5 natural numbers which are of the form 3n + 1 (e.g. 4, 7, 10, ...) and verify the following:
'The cube of a natural number of the form 3n + 1 is a natural number of the same form i.e. when divided by 3 it leaves the remainder 1'.

6Page 8

Write the cubes of 5 natural numbers of the form 3n + 2 (i.e. 5, 8, 11, ...) and verify the following:
'The cube of a natural number of the form 3n + 2 is a natural number of the same form i.e. when it is dividend by 3 the remainder is 2'.

7Page 8

Write the cubes of 5 natural numbers of which are multiples of 7 and verify the following:
'The cube of a multiple of 7 is a multiple of 73'.

8.01Page 8

Which of the following is  perfect cube? 

 64

8.02Page 8

Which of the following is  perfect cube? 

216

8.03Page 8

Which of the following is  perfect cube? 

243

8.04Page 8

Which of the following is  perfect cube? 

1000

8.05Page 8

Which of the following is  perfect cube? 

1728

8.06Page 8

Which of the following is  perfect cube? 

3087

8.07Page 8

Which of the following is  perfect cube? 

 4608

8.08Page 8

Which of the following is  perfect cube? 

 106480

8.09Page 8

Which of the following is  perfect cube? 

166375

8.1Page 8

Which of the following is  perfect cube? 

 456533

 

9Page 8

Which of the following are cubes of even natural numbers?
216, 512, 729, 1000, 3375, 13824

10Page 8

Which of the following are cubes of odd natural numbers?
125, 343, 1728, 4096, 32768, 6859

11.1Page 8

What is the smallest number by which the following number must be multiplied, so that the products is perfect cube?

675

11.2Page 8

What is the smallest number by which the following number must be multiplied, so that the products is perfect cube?

1323

11.3Page 8

What is the smallest number by which the following number must be multiplied, so that the products is perfect cube?

 2560

11.4Page 8

What is the smallest number by which the following number must be multiplied, so that the products is perfect cube?

7803

11.5Page 8

What is the smallest number by which the following number must be multiplied, so that the products is perfect cube?

107811

11.6Page 8

What is the smallest number by which the following number must be multiplied, so that the products is perfect cube?

 35721

12.1Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

675

12.2Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

8640

12.3Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

1600

12.4Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

8788

12.5Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

7803

12.6Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

107811

12.7Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

 35721

12.8Page 8

By which smallest number must the following number be divided so that the quotient is a perfect cube?

243000

13Page 8

Prove that if a number is trebled then its cube is 27 times the cube of the given number.

 
14.1Page 8

What happens to the cube of a number if the number is multiplied by 3?

14.2Page 8

What happens to the cube of a number if the number is multiplied by  4?

14.3Page 8

What happens to the cube of a number if the number is multiplied by  5?

15Page 9

Find the volume of a cube, one face of which has an area of 64 m2.

 
16Page 9

Find the volume of a cube whose surface area is 384 m2.

 
17.1Page 9

Evaluate the following: 

\[\left\{ ( 5^2 + {12}^2 )^{1/2} \right\}^3\]

 

17.2Page 9

Evaluate the following: 

\[\left\{ ( 6^2 + 8^2 )^{1/2} \right\}^3\]

 

18Page 9

Write the units digit of the cube of each of the following numbers:
31, 109, 388, 833, 4276, 5922, 77774, 44447, 125125125

19.1Page 9

Find the cubes of the following number by column method 35.

19.2Page 9

Find the cubes of the following number by column method  56 .

19.3Page 9

Find the cubes of the following number by column method 72 .

20.1Page 9

Which of the following number is  not perfect cubes?

 64

20.2Page 9

Which of the following number is  not perfect cubes? 

216

20.4Page 9

Which of the following number is  not perfect cubes? 

1728

21.1Page 9

For of the non-perfect cubes in Q. No. 20 find the smallest number by which it must be  multiplied so that the product is a perfect cube.

21.2Page 9

For of the non-perfect cubes in Q. No. 20 find the smallest number by which it must be divided so that the quotient is a perfect cube.

22.1Page 9

By taking three different values of n verify the truth of the following statement:

If n is even , then n3 is also even.

22.2Page 9

By taking three different values of n verify the truth of the following statement:

If n is odd, then n3 is also odd.

22.3Page 9

By taking three different values of n verify the truth of the following statement:

If n leaves remainder 1 when divided by 3, then n3 also leaves 1 as remainder when divided by 3.

22.4Page 9

By taking three different values of n verify the truth of the following statement:

If a natural number n is of the form 3p + 2 then n3 also a number of the same type.

23.01Page 9

Write true (T) or false (F) for the following statement:

392 is a perfect cube.

23.02Page 9

Write true (T) or false (F) for the following statement:

8640 is not a perfect cube.

23.03Page 9

Write true (T) or false (F) for the following statement:

 No cube can end with exactly two zeros.

23.04Page 9

Write true (T) or false (F) for the following statement:

There is no perfect cube which ends in 4.

23.05Page 9

Write true (T) or false (F) for the following statement:

 For an integer aa3 is always greater than a2.

23.06Page 9

Write true (T) or false (F) for the following statement:

If a and b are integers such that a2 > b2, then a3 > b3.

23.07Page 9

Write true (T) or false (F) for the following statement:

 If a divides b, then a3 divides b3.

23.08Page 9

Write true (T) or false (F) for the following statement:

 If a2 ends in 9, then a3 ends in 7.

23.09Page 9

Write true (T) or false (F) for the following statement:

 If a2 ends in 5, then a3 ends in 25.

23.1Page 9

Write true (T) or false (F) for the following statement:

 If a2 ends in an even number of zeros, then a3 ends in an odd number of zeros.

Exercise 4.2 [Page 13]

R.D. Sharma solutions for Mathematics [English] Class 8 4 Cubes and Cube Roots Exercise 4.2 [Page 13]

1.1Page 13

Find the cube of  −11 .

 

1.2Page 13

Find the cube of −12 .

1.3Page 13

Find the cube of −21 .

2.1Page 13

Which of the following number is cube of negative integer - 64 .

2.2Page 13

Which of the following number is cube of negative integer - 1056 .

2.3Page 13

Which of the following number is cube of negative integer - 2197.

2.4Page 13

Which of the following number is cube of negative integer - 2744 .

2.5Page 13

Which of the following number is cube of negative integer - 42875 .

3.1Page 13

Show that the following integer is cube of negative integer. Also, find the integer whose cube is the given integer −5832 .

 

3.2Page 13

Show that the following integer is cube of negative integer. Also, find the integer whose cube is the given integer −2744000 .

4.01Page 13

Find the cube of \[\frac{7}{9}\] .

 

4.02Page 13

Find the cube of \[- \frac{8}{11}\] . 

 

4.03Page 13

Find the cube of \[\frac{12}{7}\] .

 

 

4.04Page 13

Find the cube of \[- \frac{13}{8}\] .

 

4.05Page 13

Find the cube of \[2\frac{2}{5}\] .

 

4.06Page 13

Find the cube of:

\[3\frac{1}{4}\]

 

4.07Page 13

Find the cube of 0.3 .

4.08Page 13

Find the cube of  1.5 .

4.09Page 13

Find the cube of  0.08 .

4.1Page 13

Find the cube of 2.1 .

5.1Page 13

Find which of the following number is  cube of rational number \[\frac{27}{64}\] .

 

5.2Page 13

Find which of the following number is  cube of rational number \[\frac{125}{128}\] .

 

5.3Page 13

Find which of the following number is  cube of rational number 0.001331 .

5.4Page 13

Find which of the following number is  cube of rational number 0.04 .

Exercise 4.3 [Pages 21 - 22]

R.D. Sharma solutions for Mathematics [English] Class 8 4 Cubes and Cube Roots Exercise 4.3 [Pages 21 - 22]

1.1Page 21

Find the cube rootsof the following number by successive subtraction of number:
1, 7, 19, 37, 61, 91, 127, 169, 217, 271, 331, 397, ... 64 .

1.2Page 21

Find the cube root of the following number by successive subtraction of number:
1, 7, 19, 37, 61, 91, 127, 169, 217, 271, 331, 397, ... 512 .

1.3Page 21

Find the cube root of the following number by successive subtraction of number:
1, 7, 19, 37, 61, 91, 127, 169, 217, 271, 331, 397, ... 1728 .

2.1Page 21

Using the method of successive subtraction examine whether or not the following numbers is perfect cube 130 .

2.2Page 21

Using the method of successive subtraction examine whether or not the following numbers is perfect cube 345 .

2.3Page 21

Using the method of successive subtraction examine whether or not the following numbers is perfect cube 792 . 

2.4Page 21

Using the method of successive subtraction examine whether or not the following numbers is perfect cube 1331 .

3Page 21

Find the smallest number that must be subtracted from those of the numbers in question 2 which are not perfect cubes, to make them perfect cubes. What are the corresponding cube roots?

4.01Page 22

Find the cube root of the following natural number 343 .

4.02Page 22

Find the cube root of the following natural number 2744 .

4.03Page 22

Find the cube root of the following natural number 4913 .

4.04Page 22

Find the cube root of the following natural number 1728 .

4.05Page 22

Find the cube root of the following natural number 35937 .

4.06Page 22

Find the cube root of the following natural number 17576 .

4.07Page 22

Find the cube root of the following natural number 134217728 .

4.08Page 22

Find the cube root of the following natural number 48228544 .

4.09Page 22

Find the cube root of the following natural number 74088000 .

4.1Page 22

Find the cube root of the following natural number 157464 .

4.11Page 22

Find the cube root of the following natural number 1157625 .

4.12Page 22

Find the cube root of the following natural number 33698267 .

5Page 22

Find the smallest number which when multiplied with 3600 will make the product a perfect cube. Further, find the cube root of the product.

6Page 22

Multiply 210125 by the smallest number so that the product is a perfect cube. Also, find out the cube root of the product.

 
7Page 22

What is the smallest number by which 8192 must be divided so that quotient is a perfect cube? Also, find the cube root of the quotient so obtained.

8Page 22

Three numbers are in the ratio 1 : 2 : 3. The sum of their cubes is 98784. Find the numbers.

9Page 22

The volume of a cube is 9261000 m3. Find the side of the cube.

 
Exercise 4.4 [Pages 30 - 31]

R.D. Sharma solutions for Mathematics [English] Class 8 4 Cubes and Cube Roots Exercise 4.4 [Pages 30 - 31]

1.1Page 30

Find the cube root of the following integer −125 .

1.2Page 30

Find the cube root of the following integer  −5832 .

1.3Page 30

Find the cube root of the following integer −2744000 .

1.4Page 30

Find the cube root of the following integer −753571.

1.5Page 30

Find the cube root of the following integer −32768 .

2.1Page 30

Show that:  \[\sqrt[3]{27} \times \sqrt[3]{64} = \sqrt[3]{27 \times 64}\]

2.2Page 30

Show that: \[\sqrt[3]{64 \times 729} = \sqrt[3]{64} \times \sqrt[3]{729}\]

2.3Page 30

Show that: \[\sqrt[3]{- 125 \times 216} = \sqrt[3]{- 125} \times \sqrt[3]{216}\]

2.4Page 30

Show that:\[\sqrt[3]{- 125 - 1000} = \sqrt[3]{- 125} \times \sqrt[3]{- 1000}\]

3.1Page 30

Find the cube root of the following number  8 × 125 .

3.2Page 30

Find the cube root of the following number −1728 × 216 .

3.3Page 30

Find the cube root of the following number −27 × 2744 .

3.4Page 30

Find the cube root of the following number −729 × −15625 .

4.1Page 30

Evaluate  :  \[\sqrt[3]{4^3 \times 6^3}\]

 

4.2Page 30

Evaluate: \[\sqrt[3]{8 \times 17 \times 17 \times 17}\]

4.3Page 30

Evaluate: \[\sqrt[3]{700 \times 2 \times 49 \times 5}\]

4.4Page 30

Evaluate:  \[125\sqrt[3]{\alpha^6} - \sqrt[3]{125 \alpha^6}\]

5.1Page 30

Find the cube root of the following rational number \[\frac{- 125}{729}\] .

5.2Page 30

Find the cube root of the following rational number \[\frac{10648}{12167}\] .

5.3Page 30

Find the cube root of the following rational number \[\frac{- 19683}{24389}\] .

5.4Page 30

Find the cube root of the following rational number  \[\frac{686}{- 3456}\] .

5.5Page 30

Find the cube root of the following rational number \[\frac{- 39304}{- 42875}\] .

6.1Page 30

Find the cube root of the following rational number 0.001728 .

6.2Page 30

Find the cube root of the following rational number 0.003375 .

6.3Page 30

Find the cube root of the following rational number 0.001 .

6.4Page 30

Find the cube root of the following rational number  1.331 .

7.1Page 30

Evaluate of the following

\[\sqrt[3]{27} + \sqrt[3]{0 . 008} + \sqrt[3]{0 . 064}\]

 

7.2Page 30

Evaluate of the following

\[\sqrt[3]{1000} + \sqrt[3]{0 . 008} - \sqrt[3]{0 . 125}\]

7.3Page 30

Evaluate of the following

\[\sqrt[3]{\frac{729}{216}} \times \frac{6}{9}\]

7.4Page 30

Evaluate of the following

\[\sqrt[3]{\frac{0 . 027}{0 . 008}} \div \sqrt[]{\frac{0 . 09}{0 . 04}} - 1\]

7.5Page 30

Evaluate of the following

\[\sqrt[3]{0 . 1 \times 0 . 1 \times 0 . 1 \times 13 \times 13 \times 13}\]

8.1Page 30

Show that:

\[\frac{\sqrt[3]{729}}{\sqrt[3]{1000}} = \sqrt[3]{\frac{729}{1000}}\]

8.2Page 30

Show that: 

\[\frac{\sqrt[3]{- 512}}{\sqrt[3]{343}} = \sqrt[3]{\frac{- 512}{343}}\]

9.1Page 30

\[\sqrt[3]{125 \times 27} = 3 \times . . .\]

9.2Page 30

\[\sqrt[3]{8 \times . . .} = 8\]

9.3Page 30

\[\sqrt[3]{1728} = 4 \times . . .\]

9.4Page 30

\[\sqrt[3]{480} = \sqrt[3]{3} \times 2 \times \sqrt[3]{. . .}\]

9.5Page 30

\[\sqrt[3]{} . . . = \sqrt[3]{7} \times \sqrt[3]{8}\]

9.6Page 30

\[\sqrt[3]{. . .} = \sqrt[3]{4} \times \sqrt[3]{5} \times \sqrt[3]{6}\]

9.7Page 30

\[\sqrt[3]{\frac{27}{125}} = \frac{. . .}{5}\]

9.8Page 30

\[\sqrt[3]{\frac{729}{1331}} = \frac{9}{. . .}\]

9.9Page 30

\[\sqrt[3]{\frac{512}{. . .}} = \frac{8}{13}\]

10Page 30

The volume of a cubical box is 474.552 cubic metres. Find the length of each side of the box.

11Page 30

Three numbers are to one another 2 : 3 : 4. The sum of their cubes is 0.334125. Find the numbers.

 
12Page 30

Find the side of a cube whose volume is\[\frac{24389}{216} m^3 .\]

 
13.1Page 31

Evaluate:

\[\sqrt[3]{36} \times \sqrt[3]{384}\]

 

13.2Page 31

Evaluate:

\[\sqrt[3]{96} \times \sqrt[3]{144}\]

13.3Page 31

Evaluate: 

\[\sqrt[3]{100} \times \sqrt[3]{270}\]

 

13.4Page 31

Evaluate: 

\[\sqrt[3]{121} \times \sqrt[3]{297}\]

 

14.1Page 31

Find The cube root of the numbers 3048625, 20346417, 210644875, 57066625 using the fact that 3048625 = 3375 × 729 .

14.2Page 31

Find The cube root of the numbers 3048625, 20346417, 210644875, 57066625 using the fact that 20346417 = 9261 × 2197 .

14.3Page 31

Find The cube root of the numbers 3048625, 20346417, 210644875, 57066625 using the fact that  210644875 = 42875 × 4913 .

14.4Page 31

Find The cube root of the numbers 3048625, 20346417, 210644875, 57066625 using the fact that 57066625 = 166375 × 343 .

15.1Page 31

Find the  units digit of the cube root of the following number 226981 .

15.2Page 31

Find the  units digit of the cube root of the following number  13824 .

15.3Page 31

Find the  units digit of the cube root of the following number 571787 .

15.4Page 31

Find the  units digit of the cube root of the following number 175616 .

16Page 31

Find the tens digit of the cube root of each of the numbers in Q. No. 15.

 
Exercise 4.5 [Page 36]

R.D. Sharma solutions for Mathematics [English] Class 8 4 Cubes and Cube Roots Exercise 4.5 [Page 36]

1Page 36

Making use of the cube root table, find the cube roots 7

 
2Page 36

Making use of the cube root table, find the cube root 70 .

3Page 36

Making use of the cube root table, find the cube root
700

4Page 36

Making use of the cube root table, find the cube root
7000

5Page 36

Making use of the cube root table, find the cube root
1100 .

6Page 36

Making use of the cube root table, find the cube root
780 .

7Page 36

Making use of the cube root table, find the cube root
7800

8Page 36

Making use of the cube root table, find the cube root
1346.

9Page 36

Making use of the cube root table, find the cube root
250.

10Page 36

Making use of the cube root table, find the cube root
5112 .

11Page 36

Making use of the cube root table, find the cube root
9800 .

12Page 36

Making use of the cube root table, find the cube root
732 .

13Page 36

Making use of the cube root table, find the cube root
7342 .

14Page 36

Making use of the cube root table, find the cube root
133100 .

15Page 36

Making use of the cube root table, find the cube root
37800 .

16Page 36

Making use of the cube root table, find the cube root
0.27

17Page 36

Making use of the cube root table, find the cube root
8.6 .

18Page 36

Making use of the cube root table, find the cube root
0.86 .

19Page 36

Making use of the cube root table, find the cube root
8.65 .

20Page 36

Making use of the cube root table, find the cube root
7532 . 

21Page 36

Making use of the cube root table, find the cube root
833 .

22Page 36

Making use of the cube root table, find the cube root
34.2 .

23Page 36

What is the length of the side of a cube whose volume is 275 cm3. Make use of the table for the cube root. 

Solutions for 4: Cubes and Cube Roots

Exercise 4.1Exercise 4.2Exercise 4.3Exercise 4.4Exercise 4.5
R.D. Sharma solutions for Mathematics [English] Class 8 chapter 4 - Cubes and Cube Roots - Shaalaa.com

R.D. Sharma solutions for Mathematics [English] Class 8 chapter 4 - Cubes and Cube Roots

Shaalaa.com has the CBSE Mathematics Mathematics [English] Class 8 CBSE solutions in a manner that help students grasp basic concepts better and faster. The detailed, step-by-step solutions will help you understand the concepts better and clarify any confusion. R.D. Sharma solutions for Mathematics Mathematics [English] Class 8 CBSE 4 (Cubes and Cube Roots) include all questions with answers and detailed explanations. This will clear students' doubts about questions and improve their application skills while preparing for board exams.

Further, we at Shaalaa.com provide such solutions so students can prepare for written exams. R.D. Sharma textbook solutions can be a core help for self-study and provide excellent self-help guidance for students.

Concepts covered in Mathematics [English] Class 8 chapter 4 Cubes and Cube Roots are Concept of Cube Number, Concept of Cube Root, Cube Root Through Prime Factorisation Method, Finding the Cube Roots of the Cubic Numbers Through the Estimation Method, Patterns in Numbers.

Using R.D. Sharma Mathematics [English] Class 8 solutions Cubes and Cube Roots exercise by students is an easy way to prepare for the exams, as they involve solutions arranged chapter-wise and also page-wise. The questions involved in R.D. Sharma Solutions are essential questions that can be asked in the final exam. Maximum CBSE Mathematics [English] Class 8 students prefer R.D. Sharma Textbook Solutions to score more in exams.

Get the free view of Chapter 4, Cubes and Cube Roots Mathematics [English] Class 8 additional questions for Mathematics Mathematics [English] Class 8 CBSE, and you can use Shaalaa.com to keep it handy for your exam preparation.

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