Mathematics Questions and Answers – Finding Square Roots

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This set of Mathematics Multiple Choice Questions & Answers (MCQs) focuses on “Finding Square Roots”.

1. Square root is _________ function of square.
a) converse
b) inverse
c) polynomial
d) linear
View Answer

Answer: b
Explanation: Square root is inverse function of square. The statement can be derived by having a look on the graphs of both square and square root. The nature of graph of square is parabolic and that of square root is rectangular hyperbola. The other method here can be by observing the power which is 2 in case of square and \(\frac{1}{2}\) in case of square root.
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2. If (±2)2=4 then, √4 = ________
a) -2
b) 2
c) 4
d) -4
View Answer

Answer: b
Explanation: Here the correct answer is 2 and the others are incorrect. The options other then 2 cannot be correct because √, this symbol is used to indicate that the square roots are positive.

3. Find square root of 169.
a) 13
b) 14
c) -14
d) 12
View Answer

Answer: a
Explanation: Here we can simply find our answer by taking square root of the number \(\sqrt{169}\)=13. There can be some smart ways to find the answer without calculating the roots. A square of number ending with 9 is a square of a number ending with 3. There is only one option ending with 3. Therefore the correct answer is 13 and the others are incorrect.
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4. What is the square roots of a three digit number ending with one?
a) 1
b) 11
c) 121
d) 9
View Answer

Answer: b
Explanation: If a three digit number which is ending with 1 the square root would be ending with 1 or 9. Here all the options either have 9 or 1 at the ending. The option which has 1 cannot be the answer since the square wouldn’t be a three digit number. Similarly with the options 121 and 9 their square won’t be three digit numbers either. So, the correct answer will be 11, the square of 11 is a three digit number and ends with 1.

5. Square root of 25 is 4.
a) True
b) False
View Answer

Answer: b
Explanation: The given statement is mathematically wrong as square root of 25 is 5 and not 4. Hence the correct option would be false. Here is the statement would be that Square root of 16 is 4 then the statement would be true.
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6. Square root of 16 is ________
a) -4
b) 4
c) 16
d) -16
View Answer

Answer: b
Explanation: Since square roots cannot be negative the options stating -4 &-16 are ruled out. Now we are left with two more options from which the 16 cannot be the answer as the square root of any number cannot be that number itself . So the only answer left is 4. Hence 4 is the correct answer.

7. Find the square root of 961.
a) 31
b) 39
c) 29
d) 21
View Answer

Answer: a
Explanation: Here the trick of checking the last digit of square and square roots fails because if any square has 1 in one’s place the square root can have either 1 or 9 in its ones place. So here we calculate the square root. After calculating we get the square root as 31.
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8. If a perfect square ends with 1 then the square root can be ending with ___ & ___
a) 9 & 2
b) 9 & 1
c) 1 & 8
d) 1 & 2
View Answer

Answer: b
Explanation: When a perfect square ends with 1 its roots can be either ending with 1 or ending with 9. Hence the options other the 9 & 1 are incorrect.

9. Match the following.

Column A (Squares) Column B ( Square Roots)
i. 4 a. 4
ii. 16 b. 3
iii. 1 c. 2
iv. 9 d. 1
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Choose the correct match.
a) (i)-(c); (ii)-(a); (iii)-(d); (iv)-(b)
b) (i)-(b); (ii)-(a); (iii)-(d); (iv)-(c)
c) (i)-(c); (ii)-(d); (iii)-(a); (iv)-(b)
d) (i)-(a); (ii)-(c); (iii)-(d); (iv)-(b)
View Answer

Answer: a
Explanation: Here we need be careful while choosing the correct option as the options may look similar but are not the same. We need to select squares from column A and their appropriate roots in column B. Here the correct ordered sequence of answer is (i)-(c); (ii)-(a); (iii)-(d); (iv)-(b) and the other options are incorrect.

10. Find the root of 12321.
a) 11
b) 111
c) 1111
d) 11111
View Answer

Answer: b
Explanation: This question is basically based on the pattern that is shown by the squares of numbers containing 1 in all the digits. So the square root of the number 12321 would be 111 according to the pattern. Therefore the option containing 111 and all the other options would be incorrect.

Sanfoundry Global Education & Learning Series – Mathematics – Class 8.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter