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3901.

Which figure is formed by three noncollinear points?

Answer»

Three non-collinear points form a triangle.

3902.

The following table shows points on a number line and their co-ordinates. Decide whether the pair of segments given below the table are congruent or not.PointABCDECo-ordinate-352-79i. seg DE and seg ABii. seg BC and seg ADiii. seg BE and seg AD

Answer»

i. Co-ordinate of the point E is 9.

 Co-ordinate of the point D is -7. 

 Since, 9 > -7 

∴ d(D, E) = 9 – (-7) = 9 + 7 = 16 

∴ l(DE) = 16 …(i) 

Co-ordinate of the point A is -3.

Co-ordinate of the point B is 5.

 Since, 5 > -3 

∴ d(A, B) = 5 – (-3) = 5 + 3 = 8 

∴ l(AB) = 8 …(ii)

∴ l(DE) ≠ l(AB) …[From (i) and (ii)] 

∴ seg DE and seg AB are not congruent

ii. Co-ordinate of the point B is 5.

 Co-ordinate of the point C is 2. 

 Since, 5 > 2 

∴ d(B, C) = 5 – 2 = 3 

∴ l(BC) = 3 …(i) 

Co-ordinate of the point A is -3. 

Co-ordinate of the point D is -7.

 Since, -3 > -7 

∴ d(A, D) = -3 – (-7) = -3 + 7 = 4 

∴ l(AD) = 4 . ..(ii) 

∴ l(BC) ≠ l(AD) … [From (i) and (ii)] 

∴ seg BC and seg AD are not congruent.

 iii. Co-ordinate of the point E is 9.

 Co-ordinate of the point B is 5.

Since, 9 > 5 

∴ d(B, E) = 9 – 5 = 4 

∴ l(BE) = 4 …(i) 

Co-ordinate of the point A is -3. 

Co-ordinate of the point D is -7.

 Since, -3 > -7

 ∴ d(A, D) = -3 – (-7) = 4 

∴ l(AD) = 4 …(ii) 

∴ l(BE) =l(AD) …[From (i) and (ii)] 

∴ seg BE and seg AD are congruent. 

i.e, seg BE ≅ seg AD

3903.

If x denotes the digit at hundreds place of the number \(\overline{67\times19}\) such that the number is divisible by 11. Find all possible values of x.

Answer»

Here, given number is \(\overline{67\times19}\)

We know that a number is divisible by 11 if and only if the difference between the sum of odd and even place digits is a multiple of 11. 

∴ Sum of even placed digits – Sum of odd placed digits = 0, 11, 22,… 

∴ (6 + x + 9) – ( 7+1) = 0, 11, 22,… 

∴ x + 7 is a multiple of 11 

∴ x + 7 = 11 ∴ x = 4

3904.

The following table shows points on a number line and their co-ordinates. Decide whether the pair of segments given below the table are congruent or not.PointABCDECo-ordinate-352-79i. seg DE and seg AB ii. seg BC and seg AD iii. seg BE and seg AD

Answer»

i. Co-ordinate of the point E is 9. 

Co-ordinate of the point D is -7. 

Since, 9 > -7 

∴ d(D, E) = 9 – (-7) = 9 + 7 = 16 

∴ l(DE) = 16 …(i)

Co-ordinate of the point A is -3. 

Co-ordinate of the point B is 5. 

Since, 5 > -3 

∴ d(A, B) = 5 – (-3) = 5 + 3 = 8 

∴ l(AB) = 8 …(ii) 

∴ l(DE) ≠ l(AB) …[From (i) and (ii)] 

∴ seg DE and seg AB are not congruent.

ii. Co-ordinate of the point B is 5. 

Co-ordinate of the point C is 2. 

Since, 5 > 2 

∴ d(B, C) = 5 – 2 = 3 

∴ l(BC) = 3 …(i) 

Co-ordinate of the point A is -3. 

Co-ordinate of the point D is -7. 

Since, -3 > -7 

∴ d(A, D) = -3 – (-7) = -3 + 7 = 4 

∴ l(AD) = 4 . ..(ii) 

∴ l(BC) ≠ l(AD) … [From (i) and (ii)] 

∴ seg BC and seg AD are not congruent.

iii. Co-ordinate of the point E is 9. 

Co-ordinate of the point B is 5. 

Since, 9 > 5 

∴ d(B, E) = 9 – 5 = 4 

∴ l(BE) = 4 …(i) 

Co-ordinate of the point A is -3. 

Co-ordinate of the point D is -7. 

Since, -3 > -7 

∴ d(A, D) = -3 – (-7) = 4 

∴ l(AD) = 4 …(ii) 

∴ l(BE) =l(AD) …[From (i) and (ii)] 

∴ seg BE and seg AD are congruent. 

i.e, seg BE ≅ seg AD

3905.

Co-ordinates of some pairs of points are given below. Hence find the distance between each pair.i. 3,6 ii. -9, -1 iii. A, 5 iv. 0,-2 v. x + 3, x – 3 vi. -25, -47 vii. 80, -85

Answer»

i. Co-ordinate of first point is 3. 

Co-ordinate of second point is 6. 

Since, 6 > 3 

∴ Distance between the points = 6 – 3 = 3

ii. Co-ordinate of first point is -9. 

Co-ordinate of second point is -1. 

Since, -1 > -9 

∴ Distance between the points = -1 – (-9) = -1 + 9 = 8

iii. Co-ordinate of first point is -4. 

Co-ordinate of second point is 5. 

Since, 5 > -4 

∴ Distance between the points = 5 – (-4) = 5 + 4 = 9

iv. Co-ordinate of first point is 0. 

Co-ordinate of second point is -2. 

Since, 0 > – 2 

∴ Distance between the points = 0 – (-2) = 0 + 2 = 2

v. Co-ordinate of first point is x + 3. 

Co-ordinate of second point is x – 3. 

Since, x + 3 > x – 3

∴ Distance between the points = x + 3 – (x – 3) 

= x + 3 – x + 3 = 3 + 3 = 6 

vi. Co-ordinate of first point is -25. 

Co-ordinate of second point is -47. 

Since, -25 > -47 

∴ Distance between the points = -25 – (-47) = -25 + 47 = 22

vii. Co-ordinate of first point is 80. 

Co-ordinate of second point is -85. 

Since, 80 > -85 

∴ Distance between the points = 80 – (-85) = 80 + 85 = 165

3906.

Find all possible values of y for which the 4-digit number 64y3 is divisible by 9. Also, find the numbers.

Answer»

We know that if sum of digits of a number is divisible by 9, then the number is divisible by 9. 

Here, 

6 + 4 + y + 3 = multiple of 9 

y + 13= 0, 9, 18, … 

Hence, 

y + 13 = 18 

∴ y = 5 

The number will be 6453.

3907.

Find d(A, B), if co-ordinates of A and B are – 2 and 5 respectively. (A) -2 (B) 5 (C) 7 (D) 3

Answer»

(C) 7

Since, 5 > -2

∴ d(A, B) = 5 – (-2) = 5+2 = 7

3908.

What least number must be added to 521 to make it a perfect square? A. 3 B. 4 C. 5 D. 8

Answer»

For making 521 a perfect square, we have to add 8 on it as: 

521 + 8 = 529 

And we know that,

\(\sqrt{529}=23\)

Hence, option (D) is correct

3909.

What least number must be subtracted from 178 to make it a perfect square? A. 6 B. 8 C. 9 D. 7

Answer»

For making 178 a perfect square we have to subtract 9 from it as: 

178 – 9 = 169 

And we know that,

\(\sqrt{169}=13\)

Therefore, option (C) is correct

3910.

How many lines are determined by three distinct points? (A) two(B) three (C) one or three(D) six

Answer»

Correct option is (C) one or three

3911.

How many points are there in the intersection of two distinct lines?(A) infinite (B) two (C) one(D) not a single

Answer»

Correct option is (C) one

3912.

If \(\overline{3\times2}\) is a multiple of 11, where x is a digit, what is the value of x?

Answer»

Here, given number is \(\overline{3\times2}\)

We know that a number is divisible by 11 if and only if the difference between the sum of odd and even place digits is a multiple of 11. 

∴ Sum of even placed digits – Sum of odd placed digits = 0, 11, 22,… 

∴ x – ( 3+2) = 0, 11, 22,… 

∴ x – 5 is a multiple of 11 

∴ x – 5 = 0 ∴ x = 5

3913.

If x is a digit of the number \(\overline{66784\times}\) such that it is divisible by 9, find possible values of x.

Answer»

Here it is given that \(\overline{66784\times}\) is divisible by 9. 

We know that if a number is divisible by 9, then sum of digits must be a multiple of 9. 

∴ 6 + 6 + 7 + 8 + 4 + x = multiple of 9 

∴ x + 31 = 0,9,18,27,….. But ‘x’ is a digit, 

hence, 

‘x’ can have value between 0 to 9. 

∴ x + 31 = 36. 

∴ x = 5

3914.

Given that the number \(\overline{35a64}\) is divisible by 3, where a is a digit, what are the possible values of a?

Answer»

Here it is given that \(\overline{35a64}\) is divisible by 3.

We know that if a number is divisible by 3, then sum of digits must be a multiple of 3. 

∴ 3 + 5+a+6+4 = multiple of 3 

∴ a + 18 = 0,3,6,9,12,15,….. 

But ‘a’ is a digit, hence, ‘a’ can have value between 0 to 9. 

∴ a + 18 = 18 which gives a = 0. 

∴ a + 18 = 21 which gives a = 3. 

∴ a + 18 = 24 which gives a = 6. 

∴ a + 18 = 27 which gives a = 9. 

∴ a = 0,3,6,9

3915.

If P – Q – R and d(P, Q) = 2, d(P, R) = 10, then find d(Q, R). (A) 12 (B) 8 (C) √96 (D) 20

Answer»

(B) 8

d(P, R) = d(P, Q) + d(Q, R) 

∴ 10 = 2 + d(Q, R) 

∴ d(Q, R) = 8

3916.

Solved each of the following Cryptarithms:\(\frac{\begin{matrix}A & B & 7\\+7 & A & B\end{matrix}}{9\,\,\,\,\,\,\,\,8\,\,\,\,\,\,A}\)

Answer»

For unit’s place, 

We have two conditions, when 7 + B ≤ 9 and 7 + B > 9 

For 7 + B ≤ 9 

7 + B = A 

∴ A – B = 7 …(1) 

In ten’ place, 

B + A = 8 …(2) 

Solving 1 and 2 simultaneously, 

2A = 15 which means A = 7.5 which is not possible 

Hence, our condition 7 + B ≤ 9 is wrong. 

∴ 7 + B > 9 is correct condition 

Hence, carrying one in ten’s place and subtracting 10 from unit’s place, 

7 + B – 10 = A 

∴ B – A = 3 … (3) 

For ten’s place, 

B + A + 1 = 8 

∴ B + A =7 …(4) 

Solving 3 and 4 simultaneously, 

2B = 10 

∴ B = 5 and A = 2

3917.

Class 8 Maths MCQ Questions of Squares and Square Roots with Answers?

Answer»

Students can also reach out to Sarthaks to get Important Questions for Class 8 Maths for all other chapters. Sarthaks eConnect is a platform that provides study materials for students. Multiple Choice Questions for Class 8 are given here. Each problem carries four options, in which one is the correct answer. You can solve the Class 8 Maths MCQ Questions of square and square roots with Answers for your extensive revision for exams.

Students have to find a solution for each problem and choose the correct answer. These important questions with solutions will definitely benefit all students with revision and mastering the topic. you will learn the concepts of square and square roots. There are many important questions given for the chapter that will give you an idea of what kind of question you can expect in exams.

Practice MCQ Question for Class 8 Maths chapter-wise

1. A perfect square number between 30 and 40 is

(a) 36
(b) 32
(c) 33
(d) 39

2. Find perfect square numbers between 50 and 60

(a) 50, 54
(b) 52,58
(c) 56,59
(d) None of the above

3. Which of the following is a perfect square number?

(a) 1067
(b) 7828
(c) 4333
(d) 625

4. Which of 1322, 872, 722, and 2092 would end with digit 1?

(a) 1322
(b) 872
(c) 722
(d) 2092

5. Which of 1052, 2162, 3332, and 1112 would end with digit 1?

(a) 1052
(b) 2162
(c) 3332
(d) 1112

6. What will be the number of zeros in the square of the number 60?

(a) 1
(b) 2
(c) 3
(d) 4

7. The square of which of the following numbers will be even? 11, 111, 1111, 112

(a) 11
(b) 111
(c) 1111
(d) 112

8. The square of which of the following numbers will be odd ? 10, 100, 1000, 99

(a) 10
(b) 100
(c) 1000
(d) 99

9. Write the correct answer from the given four options. How many natural numbers lie between 52 and 62?

(a) 9
(b) 10
(c) 11
(d) 12

10. How many numbers lie between the squares of 20 and 21

(a) 10
(b) 40
(c) 5
(d) 60

11. How many non-square numbers lie between the pairs of numbers 1002 and 1012 :

(a) 200
(b) 400
(c) 500
(d) 600

12. How many non-square numbers lie between the pairs of numbers 902 and 912 :

(a) 200
(b) 400
(c) 180
(d) 240

13. What will be the unit digit of the squares of the number 81?

(a) 1
(b) 2
(c) 4
(d) 6

14. The unit digit in the square of the number 1333 is

(a) 3
(b) 6
(c) 9
(d) 1

15. The unit digit in the square of the number 166 is

(a) 22
(b) 34
(c) 36
(d) 28

16. Which of the following is not a Pythagorean triplet?

(a) 3, 4, 5
(b) 6, 8, 10
(c) 5, 12, 13
(d) 2, 3, 4

17. The square root of 441/961 is:

(a) 21/39
(b) 37/21
(c) 21/31
(d) 11/13

18. If M is a square number, then the next immediate square number is

(a) \(M+2\sqrt M+1\)
(b) M2 + 2M
(c) M + 5
(d) none of these

19. If a square number ends in 6, the preceding figure is

(a) an odd number
(b) a composite number
(c) an even number
(d) a prime number

20. The smallest number by which 396 must be multiplied so that the product becomes a perfect square is:

(a) 5
(b) 11
(c) 3
(d) 2

21. A number added to its square gives 56. The number is:

(a) 12
(b) 9
(c) 8
(d) 7

22 .\(\sqrt{\frac{1}{16}+\frac{1}{9}}\) is 

(a) 5/12
(b) 7/12
(c) 3/12
(d) none of these

23. Which of the following will have 6 at the unit place?

(a) 192
(b) 112
(c) 242
(d) 132

24. The value of 92 – 1 is equal to:

(a) 81
(b) 80
(c) 79
(d) None of the above

25. The Pythagorean triples whose smallest number is 8:

(a) 8, 16 17
(b) 8, 17, 18
(c) 8, 15, 17
(d) 8, 15, 16

Answer:

 1. Answer: (a) 36

Explanation:  Since, 

1 x 1 = 1

2 x 2 = 4

3 x 3 = 9

4 x 4 = 16

5 x 5 = 25

6 x 6 = 36

7 x 7 = 49

Thus, 36 is a perfect square number between 30 and 40.

2. Answer: (d) None of the above

Explanation: By squaring, we get as 

1 → 1

2 → 4

3 → 9

4 → 16

5 → 25

6 → 36

7 → 49

8 → 64

From, this we can say that there is no perfect square between 50 and 60

3. Answer: (d) 625

Explanation: Perfect square numbers end with, 0, 1, 4, 5, 6, or 9 at the unit’s place.

4. Answer: (d) 2092

Explanation:  If a number has 1 or 9 in the unit’s place, then its square ends in 1.

5. Answer:(d) 1112

Explanation: If a number has 1 or 9 in the unit’s place, then its square ends in 1.

6. Answer: (b) 2

Explanation: In 60, the number of zero is 1

∴ Its square will have 2 zeros.

7. Answer: (d) 112

Explanation: ∵ 112 is even

∴ Its square will be even.

8. Answer: (d) 99

Explanation: ∵ 99 is odd

∴ Its square will be odd.

9. Answer: (b) 10

Explanation: Square of 5 = 25 and 

Square of 6 = 36 

Natural numbers lie between 25 and 36 = 26, 27, 28, 29, 30, 31, 32, 33, 34, 35.

10. Answer: (b) 40

Explanation:  20= 400

21= 441

∴number of numbers

=(441−400)−1

=40

11. Answer: (a) 200

Explanation:  Between 1002 and 1012. Here, n=100 

∴  n x 2 = 100 x 2 

= 200

∴ 200 non-square numbers lie between 1002 and 1012 .

12. Answer: (c) 180

Explanation:  Between 902 and 912

Here, n=90

∴  2 x n = 2 x 90 or 180

∴  180 non-square numbers lie between 90 and 91.

13. Answer: (a) 1

Explanation:  12 = 1. So, the unit digit will be 1.

14. Answer: (c) 9

Explanation:  32 = 9. So, the unit digit will be 9.

15. Answer: (c) 36

Explanation:  62 = 36. So, the unit digit will be 36.

16. Answer: (d) 2, 3, 4

Explanation: 32 + 4= 52 

62 + 8= 102 

52 + 12= 132 

22 + 32 ≠ 42 is not a Pythagorean triplet.

17. Answer: (c) 21/31

Explanation: The square root of 441/961 is

\(\frac{\sqrt{144}}{\sqrt{961}}=\frac{21}{31}\)

18. Answer:  (a) \(M+2\sqrt M+1\)

Explanation:  \(M+2\sqrt M+1\)

Take M = 4, a Square number.

\(M+2\sqrt M+1\) = \(4+2\sqrt4+1\)

= 4 + 2 × 2 +1

= 9

19. Answer: (a) an odd number

Explanation: Let us take some square numbers ending with 6. 

Eg: 136,196,256,676,....

By observation, we can say that the preceding figure are odd numbers.

20. Answer: (b) 11

Explanation: 396 = 2 × 2 × 3 × 3 × 11

So 396 should be multiplied by 11 to make the product a perfect square.

21. Answer: (d) 7

Explanation: A number added to its square gives 56. Let the number be x.

Hence, 

x2 +x = 56

⇒ x+ x − 56 = 0

⇒ x2  + 8x − 7x − 56 = 0

⇒ x(x+8)−7(x+8)=0

⇒ (x+8)(x−7) = 0

Hence, x=−8 or x=7

22. Answer: (a) 5/12

Explanation: \(\sqrt{\frac{1}{16}+\frac{1}{9}}\)

\(\sqrt{\frac{25}{144}}\)

= 5/12

23. Answer: (c) 242

Explanation: 242 = 24 x 24 

= 576

24. Answer: (b) 80

Explanation: 9- 1

= 81 – 1 

= 80

25. Answer: (c) 8, 15, 17

Explanation: The general form of Pythagorean triplets is 2m, m2-1, m2+1

Given, 2m = 8

So, m = 4

m2 – 1

= 4- 1

= 16-1 

= 15

m2+1

= 42 + 1

= 16+1 

= 17

Click here Practice MCQ Question for Squares and Square Roots Class 8

3918.

Simplify:(i) (√59.29 – √5.29)/ (√59.29 + √5.29)(ii) (√0.2304 + √0.1764)/ (√0.2304 – √0.1764)

Answer»

(i) (√59.29 – √5.29)/ (√59.29 + √5.29)

= √59.29 

= √5929/ √100

= 77/10

= 7.7

Now, √5.29 

= √5.29/ √100

= 23/10

= 2.3

So, (7.7 – 2.3)/ (7.7 + 2.3)

= 54/10

= 0.54

(ii) (√0.2304 + √0.1764)/ (√0.2304 – √0.1764)

  = √0.2304 

= √2304/ √10000

= 48/100

= 0.48

Now, √0.1764 

= √1764/ √10000

= 42/100

= 0.42

So, (0.48 + 0.42)/ (0.48 – 0.42)

= 0.9/0.06

= 15

3919.

A square yard has area 1764m2. From a corner of this yard, another square part of area 784 m2 is taken out for public utility. The remaining portion is divided into equal square parts. What is the perimeter of each of these equal parts?

Answer»

The area of the remaining portion = 1764 – 784 = 980 m² 

It is divided into 5, equal square parts 

∴ Each square part = \(\frac{980}{5}\) = 196 m2 

Area of each square part = 196 m2 

(side)2 = 196 

side = √196 

side = 14. 

The length of each side of the square = 14m 

Perimeter = 4 side = 4 × 14 = 56m

3920.

Show that the Crptarithm \(4\times\overline{AB} = \overline{CAB}\) does not have any solution.

Answer»

If B is multiplied by 4 then only 0 satisfies the above condition. 

Hence, for unit place to satisfy the above condition, we have, B = 0. 

Similarly for ten’s place, only 0 satisfies. 

But, AB cannot be 00 as 00 is not a two digit number. 

So, A and B cannot be equal to 0 

Hence, there is no solution satisfying the condition \(4\times\overline{AB}A = \overline{CAB}\)

3921.

Find the cube roots of the numbers 3048625, 20346417, 210644875, 57066625 using the fact that(i) 3048625 = 3375 x 729(ii) 20346417 = 9261 x 2197(iii) 210644875 = 42875 x 4913(iv) 57066625 = 166375 x 343

Answer»

(i) 3048625 = 3375 x 729

Taking cube root of the whole, we get,

\(\sqrt[3]{3048625}\) = \(\sqrt[3]{3375\times729}\)

We know that,

\(\sqrt[3]{ab}\) = \(\sqrt[3]{a\times}\) \(\sqrt[3]{b}\)

\(\sqrt[3]{3048625}\) = \(\sqrt[3]{3375}\) x \(\sqrt[3]{729}\)

Now by prime factorization,

\(\sqrt[3]{3\times3\times3\times5\times5\times5}\) x \(\sqrt[3]{9\times9\times9}\)

\(\sqrt[3]{3^3\times5^3}\times\sqrt[3]{9^3}\) 

\(\sqrt[3]{3^3}\times\) \(\sqrt[3]{5^3}\times\sqrt[3]{9^3}\)

\(3\times5\times9 = 135.\)

(ii) 20346417 = 9261 x 2197

Taking cube root of the whole,

\(\sqrt[3]{20346417}\) = \(\sqrt[3]{9261\times2197}\)

We know that,

=  \(\sqrt[3]{ab}\) = \(\sqrt[3]{a\times}\) \(\sqrt[3]{b}\)

\(\sqrt[3]{9261\times2197}\) =  \(\sqrt[3]{9261}\times\) \(\sqrt[3]{2197}\)

Now by prime factorization,

\(\sqrt[3]{3\times3\times3\times7\times7\times7}\) \(\times\sqrt[3]{13\times13\times13}\)

\(\sqrt[3]{3^3\times7^3}\times\) \(\sqrt[3]{13^3}\)

\(\sqrt[3]{3^3}\times\) \(\sqrt[3]{7^3}\times\) \(\sqrt[3]{13^3}\)

= 3 × 7 × 13 = 273.

(iii) 210644875 = 42875 x 4913

Taking cube root of the whole,

\(\sqrt[3]{210644875}\) = \(\sqrt[3]{42875\times4913}\)

We know that,

=  \(\sqrt[3]{ab}\) = \(\sqrt[3]{a\times}\) \(\sqrt[3]{b}\)

\(\sqrt[3]{42875\times4913}\) = \(\sqrt[3]{42875\times}\) \(\sqrt[3]{4913}\)

Now by prime factorization,

\(\sqrt[3]{5\times5\times5\times7\times7\times7}\) x \(\sqrt[3]{17\times17\times17}\)

\(\sqrt[3]{5^3\times7^3}\times\) \(\sqrt[3]{13^3}\)

\(\sqrt[3]{5^3}\times\) \(\sqrt[3]{7^3}\times\) \(\sqrt[3]{17^3}\)

\(5\times7\times17 = 595.\)

(iv) 57066625 = 166375 x 343

Taking cube root of the whole, we get,

\(\sqrt[3]{57066625}\) = \(\sqrt[3]{166375\times343}\)

We know that,

=  \(\sqrt[3]{ab}\) = \(\sqrt[3]{a\times}\) \(\sqrt[3]{b}\)

Now by prime factorization method,

\(\sqrt[3]{5\times5\times5\times11\times11\times11}\)\(\times\sqrt[3]{7\times7\times7}\)

\(\sqrt[3]{5^3\times11^3\times}\) \(\sqrt[3]{7^3}\)

\(\sqrt[3]{5^3}\times\sqrt[3]{11^3}\times\) \(\sqrt[3]{7^3}\)

\(5\times7\times11 = 385.\)

3922.

Find the area of a square field if its perimeter is 96m.

Answer»

Given, perimeter of the square field = 96 m

We know that, perimeter of square = 4 × side

Then,

96 = 4 × side

Side = 96/4

Side = 24 m

So, the length of the side of square = 24 m

Now,

Area of the square field = (side)2

= 242

= 576 m2

∴The area of the square field is 576m2.

3923.

The volume of a cubical box is 474. 552 cubic metres. Find the length of each side of the box.

Answer»

Given, 

Volume of a cube = 474.552 cubic metres 

V = 83,

S = side of the cube 

So, 

83 = 474.552 cubic metres

= 8 = \(\sqrt[3]{474.552}\) = \(\sqrt[3]{\frac{474552}{1000}}\) = \(\frac{\sqrt[3]{474552}}{\sqrt[3]{1000}}\)

On factorising 474552 into prime factors, we get:

474552 = 2×2×2×3×3×3×13×13×13

On grouping the factors in triples of equal factors, we get: 

474552 = {2×2×2}×{3×3×3}×{13×13×13} 

Now taking 1 factor from each group we get:

\(\sqrt[3]{474.552}\) = \(\sqrt[3]{{\{2\times2\times2\times\}}\{\times3\times3\times3\}\{13\times13\times13\}}\)

\(2\times3\times13\) = 78

Also,

\(\sqrt[3]{1000} = 10\)

∴ \(8 = \frac{\sqrt[3]{474552}}{\sqrt[3]{1000}}\) = \(\frac{78}{10} = 7.8\)

So, length of the side is 7.8m.

3924.

Find the length of each side of a cube if its volume is 512 cm3.

Answer»

From the question it is given that,

Volume of the cube = 512 cm3

We know that,

Volume of cube = side3

512 = side3

By taking cube root on both the side,

3√512 = side

Side = 3√(8 × 8 × 8)

Side = 3√ (8)3

Side = 8 cm

∴The length of each side of a cube is 8 cm.

3925.

If one side of a cube is 15m in length, find its volume.

Answer»

From the question it is given that,

Length of one side of the a cube = 15 m

We know that, volume of cube = (side)3

= 153

= 15 × 15 × 15

= 3375 m3

∴The volume of cube is 3375 m3.

3926.

State whether the statements are true (T) or false (F).If a2 ends in 9, then a3 ends in 7.

Answer»

False.

Let a2 be 72

So, 72 = 49

Then, 73 = 343

3927.

State whether the statements are true (T) or false (F).Square root of a number x is denoted by √x.

Answer»

True.

Square root of a number x is denoted by √x.

3928.

63, 64, 67, 72, 79,…………… (a) 88 (b) 86 (c) 87 (d) 98

Answer»

Correct option is : (a) 88

63, 64, 67, 72, 79, ……….. 

63, (63 + 1), (64 + 3), (67 + 5), (72 + 7),…. 

So, next number is (79 + 9) = 88

3929.

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

Answer»

Let  the ratio 2:3:4 be 2a, 3a, and 4a.

So according to the question:

(2a)3+ (3a)3+(4a)3 = 0.334125

8a3+27a3+64a3 = 0.334125

99a3 = 0.334125

a3 = 334125/1000000×99

= 3375/1000000

a = ∛(3375/1000000)

= ∛((15×15×15)/ 100×100×100)

= 15/100

= 0.15

Hence ,the numbers are:

2×0.15 = 0.30

3×0.15 = 0.45

= 4×0.15 

= 0.6

3930.

State whether the statements are true (T) or false (F).Square of a number is positive, so the cube of that number will also be positive.

Answer»

False.

Let us take -3

Now, square of the -3 i.e. -32 = 9

Then, cube of the same number i.e. -33 = -27

3931.

Fill in the blanks to make the statements true.The least number by which 72 be divided to make it a perfect cube is _____________.

Answer»

9

Resolving 72 into prime factors, we get
72=2 x 2 x 2 x 3 x 3

Grouping the factors in triplets of equal factors, we get

72 = (2 x 2 x 2) x 3 x 3

Clearly, if we divide 72 by 3 x 3, the quotient would be 2 x 2 x 2, which is a perfect cube. 

Hence, the least number by which 72 be divided to make it, a perfect cube, is 9.

3932.

Difference of two perfect cubes is 189. If the cube root of the smaller of the two numbers is 3, find the cube root of the larger number.

Answer»

From the question it is given that,

Difference of two perfect cubes = 189

The cube root of the smaller of the two numbers = 3

So, cube of smaller number = 33

= 3 × 3 × 3

= 27

Let us assume the cube root of larger number be a3

Then,

As per the condition given in the question,

a3 – 27 = 189

a3 = 189 + 27

a3 =216

By taking cube root on both side,

a = 3√216

a = 3√(6 × 6 × 6)

a = 3√(63)

a = 6

∴The cube root of the larger number is 6.

3933.

State whether the statements are true (T) or false (F).3√ (8 + 27) = 3√ (8) + 3√ (27).

Answer»

False.

Let us consider LHS = 3√ (8 + 27)

3√ (35)

Then, RHS = 3√8 + 3√27

= 2 + 3

= 5

By comparing LHS and RHS

LHS ≠ RHS

3√ (35) ≠ 5

3934.

State whether the statements are true (T) or false (F).The square root of a perfect square of n digits will have (n + 1)/2 digits, if n is odd.

Answer»

True.

Let us assume the perfect square has 9 digits, then its square root has 5 digits

i.e. (9 + 1)/2 = 10/2 = 5

3935.

Evaluate: {(52 + (122)1/2)}3

Answer»

Given, {(52 + (122)1/2)}3

= {(25 + (144)1/2)}3

= {(25 + (12)}3

= {37}3

= 37 × 37 × 37

= 50,653

3936.

What can be the unit place digit in the square root of the following numbers.(i) 9604(ii) 65536(iii) 998001(iv) 60481729

Answer»

(i) Unit place digit in the square root of 9604 = 2,8

(ii) Unit place digit in the square root of 65536 = 4,6

(iii) Unit place digit in die square root of 998001 = 1,9

(iv) Unit place digit in the square root of 60481729 = 3,7

3937.

How many numbers are there in between the following numbers?(i) 10 and 11(ii) 17 and 18(iii) 30 and 31

Answer»

(i) 10 + 11 =21 numbers

(ii) 17 + 18 = 35 numbers

(iii) 30 +31 =61 numbers

3938.

Observe the following pattern22 _ 12 = 2+132 - 22 = 3+242 - 32 = 4+352 - 42 = 5+4And find the value of(i) 1002 -992 (ii) 1112-1092 (iii)992 -962

Answer»

(i) 1002 – 992 

= 100 + 99 

= 199 

(ii) 1112 - 1092 

= 1112 – 1102 + 1102 - 1092 

= (111 + 110) + (110 + 109) 

= 440 

(iii) 992 - 962 = 992 – 982 + 982 – 972 + 972 - 962 

= (99 + 98) + (98 + 92) + (97 + 96) 

= 585

3939.

State whether the statements are true (T) or false (F).There is no cube root of a negative integer.

Answer»

False.

Let us take -27

Cube root of -27 i.e. 3√-27 

3√((-3) × (-3) × (-3))

= -3

3940.

If m is the cube root of n, then n is(a) m3 (b) √m (c) m/3 (d) 3√m

Answer»

(a) m3

Given in the question,

3√n = m

n = m3

3941.

Three numbers are in the ratio 2:3:4. The sum of their cubes is 0.334125. Find the numbers.

Answer»

Let us assume the three number be 2a, 3a, 4a

Then,

Given, sum of cube of three numbers is 0.334125

i.e. (2a)3 + (3a)3 + (4a)3 = 0.334125

8a3 + 27a3 + 64a3 = 0.334125

99a3 = 0.334125

a3 = 0.334125/99

a3 = 0.003375

a3 = 3375/1000000

a = 3√(3375/1000000)

a = 3√((15 × 15 × 15)/(10 × 10 × 10 × 10 × 10 × 10))

a = 3√(153/106)

a = 15/1000

a = 0.015

∴The numbers are, 2a = 2 × 0.015 = 0.03

3a = 3 × 0.015 = 0.045

4a = 4 × 0.015 = 0.06

3942.

Using distributive law, find the squares of 72.

Answer»

By using distributive law,

We have,

72 = 70 + 2

So,

722 = (70 + 2)2

= (70 + 2) (70 + 2)

= 70 (70 + 2) + 2 (70 + 2)

= ((70 × 70) + (70 × 2)) + ((2 × 70) + (2 × 2))

= 4900 + 140 + 140 + 4

= 5184

∴The square of the given number i.e. 722 = 5184

3943.

Evaluate: {(62 + (82)1/2)}3

Answer»

Given, {(62 + (82)1/2)}3

= {(36 + (64)1/2)}3

= {(36 + (8)}3

= {44}3

= 44 × 44 × 44

= 85,184

3944.

Which of the following triplets are Pythagorean?(i) (8, 15, 17) (ii) (18, 80, 82) (iii) (14, 48, 51) (iv) (10, 24, 26) (v) (16, 63, 65) (vi) (12, 35, 38)

Answer»

(i) (8, 15, 17) 

L.H.S = 82 + 152 = 289 

R.H.S = 172 = 289 

L.H.S = R.H.S 

So, it is Pythagoras 

(ii) (18, 80, 82) 

L.H.S = 182 + 802 = 6724 

R.H.S = 822 = 6724 

L.H.S = R.H.S 

So, it is Pythagoras 

(iii) (14, 48, 51) 

L.H.S = 142 + 482 = 2500 

R.H.S = 512 = 2601 

L.H.S ≠ R.H.S 

So, it is not Pythagoras 

(iv) (10, 24, 26) 

L.H.S = 102 + 242 = 676 

R.H.S = 262 = 676 

L.H.S = R.H.S 

So, it is Pythagoras 

(v) (16, 63, 65) 

L.H.S = 162 + 632 = 4225 

R.H.S = 652 = 4225 

L.H.S = R.H.S 

So, it is Pythagoras 

(vi) (12, 35, 38) 

L.H.S = 122 + 352 = 1369 

R.H.S = 382 = 1444 

L.H.S ≠ R.H.S 

So, it is Pythagoras

3945.

Check whether the given set of three numbers either a Pythagorean triplets or not?(i) 9,12, 15(ii) 7, 11, 13(iii) 10, 24, 26

Answer»

(i) (9)2 + (12)2 = 81 + 144 = 225 = (15)2
So (9)2 + (12)2= (15)2
or 9, 12, 15 Pythagorean triplets.

(ii) (7)2 + (11)2 = 49 + 121 = 170
∴ (7)2 + (11)2 ≠ (13)2
or 7, 11, 13 Pythagorean triplets.

(iii) (10)2 + (24)2 = 100 + 576 = 676 = (26)2
∴ (10)2 + (24)2 = (26)2
or 10, 24, 26 Pythagorean triplets.

3946.

State whether the statements are true (T) or false (F).There are five perfect cubes between 1 and 100.

Answer»

False.

There are only 3 perfect cubes between 1 and 100.

2 × 2 × 2 = 8

3 × 3 × 3 = 27

4 × 4 × 4 = 64

3947.

State whether the statements are true (T) or false (F).The cube root of 8000 is 200.

Answer»

False

3√8000 = 20

3948.

Using distributive law, find the squares of 101.

Answer»

By using distributive law,

We have,

101 = 100 + 1

So,

1012 = (100 + 1)2

= (100 + 1) (100 + 1)

= 100 (100 + 1) + 1 (100 + 1)

= ((100 × 100) + (100 × 1)) + ((1 × 100) + (1 × 1))

= 10000 + 100 + 100 + 1

= 10201

∴The square of the given number i.e. 1012 = 10201

3949.

A perfect square number has four digits, none of which is zero. The digits from left to right have values that are: even, even, odd, even. Find the number.

Answer»

Let us assume PQRS is perfect square,

Where, P = even, Q = even, R = odd, S = even

So, 8836 is the perfect square.

3950.

Fill in the blanks to make the statements true.There are _________ natural numbers between n2 and (n + 1)2.

Answer»

There are 2n natural numbers between n2 and (n + 1)2.