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Square root of perfect square

Attempted 0/81 Correct 0 Score 0

The value of $\sqrt{\dfrac{64x^{2}}{49y^{2}}}$ is

  1. $\dfrac {8x}{7y}$

  2. $\dfrac {8}{7y}$

  3. $\dfrac {8x^{4}}{7y^{2}}$

  4. $none$


Correct Option: A
Explanation:

$\sqrt{\dfrac{64x^{2}}{49y^{2}}}$


$\Rightarrow$  $\sqrt{\dfrac{(8x)^2}{(7y)^2}}$
Taking square root on both sides,

$\Rightarrow$  $\dfrac{8x}{7y}$

$\therefore$  $\sqrt{\dfrac{64x^{2}}{49y^{2}}}=\dfrac{8x}{7y}$

Find the square root of $7-4 \sqrt{3}$

  1. $2+ \sqrt{3}$

  2. $5- \sqrt{3}$

  3. $2- \sqrt{3}$

  4. $5+\sqrt{3}$


Correct Option: C
Explanation:
$7-4\sqrt 3$
$=7-2\sqrt {2\times 3}$
$=7-2\sqrt {12}$
$=(\sqrt 3)^2-2\sqrt {3\times 4}+(\sqrt 4)$
$=(-\sqrt {3}+\sqrt {4})^2$
$\therefore \ \sqrt {7-}4\sqrt {3}=2-\sqrt {3}$
$\boxed {2-\sqrt 3}$

$(1\frac{7}{9})^{-1/2} =$

  1. $\frac{4}{3}$

  2. $\frac{3}{4}$

  3. $-\frac{4}{3}$

  4. $-\frac{3}{4}$


Correct Option: B
Explanation:

$(1\frac{7}{9})^{-1/2} =(\frac{16}{9})^{-1/2}=(\frac{4}{3})^{-1}=\frac{3}{4}$

If $\displaystyle \sqrt{1+\frac{25}{144}}=\frac{x}{12}$ then x equals

  1. 1

  2. 11

  3. 13

  4. 7


Correct Option: C
Explanation:
$ \sqrt{1+\cfrac{25}{144}}=\cfrac{x}{12}$
$\Rightarrow \sqrt{\cfrac{169}{144}}=\cfrac{x}{12}$
$ \Rightarrow \cfrac{x}{12}=\cfrac{13}{12}$
$\Rightarrow x=\cfrac{13}{12}\times 12$
$\Rightarrow x=13 $

Find the square root of $\displaystyle 9\frac { 49 }{ 64 } $.


  1. $\displaystyle 3\frac { 1 }{ 8 } $.

  2. $\displaystyle 4\frac { 3 }{ 8 } $.

  3. $\displaystyle 3\frac { 7 }{ 8 } $.

  4. $\displaystyle 4\frac { 1}{ 8 } $.


Correct Option: A
Explanation:

$\sqrt { 9\displaystyle\frac { 49 }{ 64 }  } =\sqrt {\displaystyle \frac { 625 }{ 64 }  } =\displaystyle\frac { \sqrt { 625 }  }{ \sqrt { 64 }  } =\displaystyle\frac { 25 }{ 8 } =3\displaystyle\frac { 1 }{ 8 } $.

Evaluate: $\displaystyle\sqrt{5 \left(2\frac{3}{4}\, -\, \frac{3}{10}\right)}$ is $\displaystyle 3\frac{1}{m}$

$m$ is 

  1. $2$

  2. $5$

  3. $4$

  4. $6$


Correct Option: A
Explanation:

  $\sqrt{5 \left(2\dfrac{3}{4}\, -\, \dfrac{3}{10}\right)}$
$=\sqrt { 5\left( \dfrac { 11 }{ 4 } \, -\, \dfrac { 3 }{ 10 }  \right)  } $
$=\sqrt { 5\left( \dfrac { 55-6 }{ 20 } \,  \right)  } $
$ =\sqrt { \left( \dfrac { 49 }{ 4 } \,  \right)  } $
$=\dfrac{7}{2}$
$=3\dfrac{1}{2}$

Evaluate:$\displaystyle\sqrt{(0.5)^3\, \times\, 6\, \times\, 3^5}$

  1. $13.5$

  2. $13.6$

  3. $13.7$

  4. $13.8$


Correct Option: A
Explanation:

$\sqrt { { 0.5 }^{ 3 }\times6\times{ 3 }^{ 5 } } \ =\sqrt { { 0.5 }^{ 2 }\times2\times0.5\times{ 3 }^{ 6 } } \ =0.5*3^{ 3 }\quad =13.5$

Find the square root of: $\displaystyle27\frac{9}{16}$

  1. $\displaystyle2\frac{1}{4}$

  2. $\displaystyle7\frac{1}{4}$

  3. $\displaystyle3\frac{1}{4}$

  4. $\displaystyle5\frac{1}{4}$


Correct Option: D
Explanation:

Given number is $ 27\dfrac {9}{16} = \dfrac {441}{16} $

Square root of $ \dfrac {441}{16} =  \dfrac { \sqrt {441}}{\sqrt {16}} = \dfrac {21}{4} = 5 \dfrac {1}{4} $

Evaluate: $\sqrt{\displaystyle \frac{1}{16}\, +\, \displaystyle \frac{1}{9}}$

  1. $\displaystyle \frac{7}{12}$

  2. $\displaystyle \frac{25}{144}$

  3. $\displaystyle \frac{5}{12}$

  4. None of these


Correct Option: C
Explanation:

$\sqrt{\displaystyle \frac{1}{16}\, +\, \displaystyle \frac{1}{9}}\,=\sqrt{\displaystyle \frac{(1\times9)+(1\times16)}{9\times16}} =\, \sqrt{\displaystyle \frac{25}{144}}\, =\, \displaystyle \frac{5}{12}$

The square root of $71\, \times\, 72\, \times\, 73\, \times\, 74\, +\, 1$ is :

  1. 9,375

  2. 9,625

  3. 5,625

  4. 5,255


Correct Option: D
Explanation:

$\text{Here. consider the fact that the product of 4 consecutive numbers + 1 is perfect square.}$

$So, let\, x = 71$

⇒ $(71)(72)(73)*(74) + 1 = x(x + 1) (x + 2) (x + 3) +1$ 

⇒$ (x² + 3x)(x² + 3x + 2) + 1$

⇒$ (x² + 3x)² + 2(x² + 3x) + 1$

⇒ $(x² + 3x + 1)^2$

⇒ $Square \,root \,of \,(x² + 3x + 1)² = x² + 3x + 1$

$Here, x = 71$

$Therefore, square root is = (71)² + (3*71) + 1$

⇒ $5041 + 213 + 1$ 

= $5255$

The square root of $\displaystyle \frac{441}{961}$ is :

  1. $\displaystyle \frac{21}{39}$

  2. $\displaystyle \frac{37}{21}$

  3. $\displaystyle \frac{21}{31}$

  4. $\displaystyle \frac{11}{13}$


Correct Option: C
Explanation:

We have to find square root of $\displaystyle \frac {441}{961}$

$\therefore \displaystyle \frac{\sqrt{144}}{\sqrt{961}}=\frac{21}{31}$

What smallest number must be added to 269 to make it a perfect square:

  1. 31

  2. 16

  3. 7

  4. 20


Correct Option: D
Explanation:
$269$ lies between $256$ and $289$, which are squares of $16$ and $17$, respectively.
Hence, $17^{2} - 269 = 20$.
$\therefore$ We need to add $20$ to $269$ to make it a perfect square.

$\sqrt {\displaystyle \frac{0.289}{0.00121}}\, =\, ?$

  1. $\displaystyle \frac{1.7}{11}$

  2. $\displaystyle \frac{17}{11}$

  3. $\displaystyle \frac{170}{11}$

  4. $\displaystyle \frac{17}{110}$


Correct Option: C
Explanation:

$\displaystyle {\sqrt {\frac{0.289}{0.00121}}\, =\, \sqrt {\frac{0.28900}{0.00121}}\, =\, \sqrt {\frac{28900}{121}}}$ $=\cfrac{170}{11}$

$\displaystyle \frac{?}{\sqrt{2.25}}\, =\, 550$

  1. 825

  2. 82.5

  3. 3666.66

  4. 2


Correct Option: A
Explanation:
Let $ \cfrac{x}{\sqrt{2.25}} = 550$
Then, $ \cfrac{x}{1.5} = 550$
$\therefore x = (550 \times 1.5) =  {\left (\cfrac{550 \times 15}{10} \right ) = 825}$

$\sqrt{4\displaystyle\frac{57}{196}}=?$

  1. $2\displaystyle\frac{1}{14}$

  2. $2\displaystyle\frac{3}{14}$

  3. $2\displaystyle\frac{5}{14}$

  4. $2\displaystyle\frac{9}{14}$


Correct Option: A
Explanation:

$\sqrt{4\frac{57}{196}}$
$=\sqrt{\frac{841}{196}}$
$=\frac{29}{14}$
$=2\frac{1}{14}$

The value of $\sqrt{0.064}$ is

  1. 0.8

  2. 0.08

  3. 0.008

  4. 0.252


Correct Option: D
Explanation:
$\sqrt{0.064} = \sqrt{0.0640}$

$=  {\sqrt{\cfrac{640}{10000}} = \cfrac{\sqrt{640}}{100}}$

$=  \cfrac{25.2}{100} = 0.252$

$\sqrt{0.0009}\, \div\, \sqrt{0.01}\, =\, ?$

  1. 3

  2. 0.3

  3. $\displaystyle \frac{1}{3}$

  4. None of these


Correct Option: B
Explanation:
$\sqrt{0.0009} \div \sqrt{0.01}$ $=  \cfrac{\sqrt{0.0009}}{\sqrt{0.01}}$
$= \cfrac{\sqrt{0.0009}}{\sqrt{0.0100}} $
$= \sqrt{\cfrac{9}{100}}$
$= \cfrac{\sqrt{9}}{\sqrt{100}}$
$ = \cfrac{3}{10} = 0.3$

The value of $\sqrt{214+\sqrt{130-\sqrt{88-\sqrt{44+\sqrt{25}}}}}$

  1. $14$

  2. $15$

  3. $16$

  4. $17$


Correct Option: B
Explanation:

 $\sqrt{214+\sqrt{130-\sqrt{88-\sqrt{44+\sqrt{25}}}}}$
$\Rightarrow \sqrt{214+\sqrt{130-\sqrt{88-\sqrt{44+5}}}}$
$\Rightarrow \sqrt{214+\sqrt{130-\sqrt{88-\sqrt{49}}}}$
$\Rightarrow \sqrt{214+\sqrt{130-\sqrt{88-7}}}$
$\Rightarrow \sqrt{214+\sqrt{130-\sqrt{81}}}$
$\Rightarrow  \sqrt{214+\sqrt{130-9}}$
$\Rightarrow \sqrt{214+\sqrt{121}}$
$\Rightarrow \sqrt{214+11}$
$\Rightarrow \sqrt{225}=15$

The value of $\displaystyle \sqrt{1 + 2008 \sqrt{1 + 2009 \sqrt{1 + 2010 \sqrt{1 + 2011.2013}}}}$ is .............

  1. 2009

  2. 2010

  3. 2011

  4. 2013


Correct Option: A
Explanation:

$\sqrt{1+2008\sqrt{1+2009\sqrt{1+2010\sqrt{1+2011.2013}}}}$
Or $\sqrt{1+2008\sqrt{1+2009\sqrt{1+2010.2012}}}$
$\Rightarrow \sqrt{1+2008\sqrt{1+2009.2011}}$
$\Rightarrow \sqrt{1+2008.2010}$
$\Rightarrow \sqrt{4036081}=2009$

Find the square root of the following $\displaystyle\frac{2025}{4900}$

  1. $\displaystyle\frac{55}{80}$

  2. $\displaystyle\frac{55}{70}$

  3. $\displaystyle\frac{45}{80}$

  4. $\displaystyle\frac{45}{70}$


Correct Option: D
Explanation:

Let us find the square root of $2025\;and\;4900$ by factorising them.
$3\mid \; \; 2025\ { \overline { 3\mid \; \; 675 }  }\ { \overline { 3\mid \; \; 225 }  }\ { \overline { 3\mid \; \; \; \; 75 }  }\ { \overline { 5\mid \; \; \; \; 25 }  }\ { \overline { 5\mid \; \; \; \; \; 5 }  }\ { \overline { \; \; \mid \; \; \; \; 1 }  }$
$2025=\underline{3\times3}\times\underline{3\times3}\times\underline{5\times5}$
$\sqrt{2025}=3\times3\times5=45$
$2\mid \; \; 4900\ { \overline { 2\mid \; \; 2450 }  }\ { \overline { 5\mid \; \; 1225 }  }\ { \overline { 5\mid \; \; \; \; 245 }  }\ { \overline { 7\mid \; \; \; \; \;49 }  }\ { \overline { 7\mid \; \; \; \; \; \;7 }  }\ { \overline { \; \; \;\mid \; \; \; \; \;1 }  }$
$4900=\underline{2\times2}\times\underline{5\times5}\times\underline{7\times7}$
$\sqrt{4900}=2\times5\times7=70$
So, $\cfrac{\sqrt{2025}}{\sqrt{4900}}=\cfrac{45}{70}$.

If it is possible to form a number with the second, the fifth and the eighth digits of the number 31549786, which is the perfect square of a two digit even number, which of the following will be the second digit of that even number?

  1. 1

  2. 4

  3. 6

  4. No such number can be formed


Correct Option: B
Explanation:

The 2nd , 5th and 8th digit of the number 31549786 are 196 respectively.
196 is a perfect square of 14. 
Therefore, the even number required is 14.
Second digit of that number is 4.
Answer is 4

If $\sqrt{\displaystyle\frac{16}{49}}=\displaystyle\frac{n}{49}$ then $n=$

  1. $4$

  2. $7$

  3. $16$

  4. $28$


Correct Option: D
Explanation:

$\sqrt{\frac{16}{49}}=\frac{n}{49}$
$\Rightarrow \frac{4}{7}=\frac{n}{49}$
$\Rightarrow n=\frac{49\times 4}{7}=28$

If the sum $S$ of three consecutive even numbers is a perfect square between $200\;and\;400$, then the square root of $S$ is

  1. $15$

  2. $16$

  3. $18$

  4. $19$


Correct Option: C
Explanation:

$15^2=225,\;16^2=256$
$17^2=281\;18^2=324$
$19^2=361$
$\;2x-2+2x+2x+2=6(x)$
$\Rightarrow6x=324$ is possible
$\Rightarrow\sqrt{324}=18$

Therefore,square root of $S$ is $18$

Find the length of the side of a square whose area is 441 $ \displaystyle m^{2} $.

  1. $19 $ m

  2. $21 $ m

  3. $23 $ m

  4. $29 $ m


Correct Option: B
Explanation:

Given the area of the square is $441\ m^2$ .

We know the area of the square is side$^{ 2 }$
So, the square root of side is $\sqrt { 441 } =\sqrt{3\times\ 3\times 7\times 7}=3\times 7=21$.
The side of the square is $21$ m.

Two square roots of the unity are

  1. $1, -1$

  2. $-1, \omega$

  3. $1, -\omega$

  4. $i, i^2$


Correct Option: A
Explanation:

Square root of unity is 1 and  -1 as $1^2={-1}^2=1$

Inverse operation of squares is known as:

  1. minimum number

  2. square root

  3. odd number

  4. prime number


Correct Option: B
Explanation:

To get inverse ( opposite operation) of squares. Division is opposite of Multiplication.

$13 \times 13 =169$ ( Square)

$169 \div 13 = 13$ ( Square root)

Therefore, B is the correct answer

$\sqrt{0.0169 \times ?}= 1.3$

  1. 10

  2. 100

  3. 1000

  4. None of these


Correct Option: B
Explanation:

Let $\sqrt{0.0169 \times x}=1.3$
Then,  $0.0169x = (1.3)^2 = 1.69$
$\Rightarrow x=\frac{1.69}{0.0169}=100$

Solve of simplify the following problem, using the properties of roots:
$\sqrt { 20a } \times \sqrt { 5a }$, assuming $a$ is positive

  1. $10a$

  2. $12a$

  3. $15a$

  4. $5a$


Correct Option: A
Explanation:

$10a: \sqrt { 20a } \times \sqrt { 5a } =\sqrt{100{a}^{2}}=10a$

State whether true or false:
$\cfrac{\sqrt{12}}{\sqrt{3}}$ is not a rational number as $\sqrt{12}$ and $\sqrt{3}$ are not integers. 
  1. True

  2. False


Correct Option: B
Explanation:

False

$\cfrac{\sqrt{12}}{\sqrt{3}}=\sqrt{4}=2$ which is a rational number.

Value of $\sqrt{10+\sqrt{25+\sqrt{121}}}$ in the following is 

  1. 5

  2. 3

  3. 4

  4. 6


Correct Option: C
Explanation:

$\sqrt{10+\sqrt{25+\sqrt{121}}}$
$=\sqrt{10+\sqrt{15+11}}$
$=\sqrt{10+6}=\sqrt{16}=4$

Square root of $400$ is?

  1. $40$

  2. $25$

  3. $20$

  4. $100$


Correct Option: C
Explanation:

$400=2\times 200$

       $=2\times 2\times 100$
       $=2\times 2\times 2\times 50$
       $=2\times 2\times 2\times 2\times 25$
       $=2\times 2\times 2\times 2\times 5\times 5$
       $=2^4\times 5^2$
$\Rightarrow$  $400=2^4\times 5^2$
$\Rightarrow$  $\sqrt{400}=\sqrt{2^4\times 5^2}$
$\Rightarrow$  $\sqrt{400}=2^2\times 5$
$\Rightarrow$  $\sqrt{400}=4\times 5$
$\Rightarrow$  $\sqrt{400}=20$

The value  of  $\sqrt {11 - \sqrt{112} }=  $

  1. $2 + \sqrt{7}$

  2. $2 - \sqrt{7}$

  3. $ \sqrt{7} - 2$

  4. none of these


Correct Option: C
Explanation:
$11-\sqrt {112}$

$=11-\sqrt {4\times 28}$

$=11-\sqrt {4}\times \sqrt {28}$

$=11-2\times \sqrt {28}$

$=11-2\times \sqrt {7}\times \sqrt {4}$

$=7+4-2\times \sqrt {7}\times \sqrt {4}$

$=(\sqrt {7})^2 +(\sqrt {4})^2 -2\times \sqrt {7}\times \sqrt {4}$

$=(\sqrt {7}-\sqrt {4})^2$

Thus, $11-\surd {112}=(\surd {7} -\surd {4})^2$

Hence,

$\sqrt {11-\sqrt {112}}=\sqrt {(\sqrt {7}-\sqrt {4})^2}=\sqrt {7}-\sqrt {4}=\sqrt {7}-2$

The square root of $289$ is?

  1. $13$

  2. $17$

  3. $27$

  4. $23$


Correct Option: B
Explanation:

$289 = 17 × 17$
$\text{So, square root of 289 is 17.}$ 

Simplify the following: 
$\displaystyle \frac{\sqrt{24}}{8}+\frac{\sqrt{54}}{9}$ is equal to $\displaystyle \frac{7\sqrt{6}}{12}$
If true then enter $1$ and if false then enter $0$

  1. $1$

  2. $0$

  3. Cannot be determined, incomplete information

  4. None of the above


Correct Option: A
Explanation:

$ =\dfrac { 9\sqrt { 2\times 2\times 2\times 3 } +8\sqrt { 2\times 3\times 3\times 3 }  }{ 72 } $
$ = \dfrac { 18\sqrt { 6 } +24\sqrt { 6 }  }{ 72 } $
$ = \dfrac { 42\sqrt { 6 }  }{ 72 } $
$ = \dfrac { 7\sqrt { 6 }  }{ 12 }  $

The value of $\cfrac { 10\sqrt { 6.25 }  }{ \sqrt { 6.25} - 0.5 } $ is
  1. $125$

  2. $0.125$

  3. $1.25$

  4. $12.5$


Correct Option: D
Explanation:

$\cfrac { 10\sqrt { 6.25 }  }{ \sqrt { 6.25-0.5 }  } =\cfrac { 10\times 2.5 }{ 2.5-0.5 } =\cfrac { 25 }{ 2 } =12.5$

If ${\left( {\dfrac{m}{n}} \right)^{\dfrac{3}{8}}} + {\left( {\dfrac{n}{m}} \right)^{\dfrac{3}{8}}} = 9$ then find the value of ${\left( {\dfrac{m}{n}} \right)^{\dfrac{3}{4}}} + {\left( {\dfrac{n}{m}} \right)^{\dfrac{3}{4}}}$

  1. $79$

  2. $72$

  3. $83$

  4. $84$


Correct Option: A
Explanation:
$(\dfrac{m}{n})^\dfrac{3}{8}+(\dfrac{n}{m})^\dfrac{3}{8}=9$
$[(\dfrac{m}{n})^\dfrac{3}{8}+(\dfrac{n}{m})^\dfrac{3}{8}]^{2} =9^{2}$
$ ((\dfrac{m}{n})^\dfrac{3}{8})^{2}+((\dfrac{n}{m})^\dfrac{3}{8})^{2}+2((\dfrac{m}{n})^\dfrac{3}{8})((\dfrac{n}{m})^\dfrac{3}{8})=81$
$ (\dfrac{m}{n})^\dfrac{3}{4}+(\dfrac{n}{m})^\dfrac{3}{4}=81-2=79$

The square root of sum of the digits in the square of $121$ is

  1. $4$

  2. $3$

  3. $6$

  4. $9$


Correct Option: A
Explanation:
${ \left( 121 \right)  }^{ 2 }$

$={ \left( 100+21 \right)  }^{ 2 }$     

$={ 100 }^{ 2 }+{ 21 }^{ 2 }+2\left( 100 \right) \left( 21 \right) $      $[\because (a+b)^2= a^2+2ab+b^2]$

$=14641$

Sum of digits $=1+4+6+4+1=16$

Square root$=\sqrt { 16 } =4$

Find the square root of $225$ using "Repeated Subtraction".

  1. $11$

  2. $15$

  3. $5$

  4. $8$


Correct Option: B
Explanation:

$\\225-1=224\\224-3=221\\221-5=216\\216-7=209\\209-9=200\\200-11=189\\189-13=176\\176-15=161\\161-17=144\\144-19=125\\125-21=104\\104-23=81\\81-25=56\\56-27=29\\29-29=0\\\>Total\>steps\>of\>=15\>\\hence\>\sqrt{225}=15$

Evaluate and state true or false 

$\displaystyle \sqrt{\frac{25}{32}\, \times\, 2\frac{13}{18}\, \times\, 0.25}$ is $\displaystyle \frac{35}{48}$

  1. True

  2. False


Correct Option: A
Explanation:

   $\sqrt{\dfrac{25}{32} \times 2\dfrac{13}{18}\times 0.25}$
$=\sqrt { \dfrac { 25 }{ 32 } \times \dfrac { 49 }{ 18 } \times \dfrac { 25 }{ 100 }  } $
$=\sqrt { \dfrac { 5^ 2 }{ 2^ 5 } \times \dfrac { 7^ 2 }{ 9\times 2 } \times \dfrac { 1 }{ 2^ 2 }  } $
$=\sqrt { \dfrac { 5^ 2 }{ 2^ 6 } \times \dfrac { 7^ 2 }{ 3^2 } \times \dfrac { 1 }{ 2^ 2 }  } $
$=\dfrac{5\times 7}{2^4\times 3}$
$=\dfrac{35}{48}$

The square root of $\displaystyle96\frac{1}{25}$ is $\displaystyle9\frac{4}{5}$
State true or false.

  1. True

  2. False


Correct Option: A
Explanation:

Given number is $ 96\frac {1}{25} = \frac {2401}{25} $

Square root of $ \frac {2401}{25} =  \frac { \sqrt {2401}}{\sqrt {25}}

= \frac {49}{5} = 9 \frac {4}{5} $

Find the least number that must be subtracted so that the resulting number is a perfect square.
1886

  1. 27

  2. 47

  3. 37

  4. 85


Correct Option: C

Evaluate: $\displaystyle\sqrt{\left (5\, +\, 2\frac{21}{25}\right )\, \times\, \frac{0.169}{1.6}}$ $\times 100$

  1. $91$

  2. $81$

  3. $21$

  4. $54$


Correct Option: A
Explanation:

$\sqrt{\left (5+2\dfrac{21}{25}\right )\times \dfrac{0.169}{1.6}}\times 100$

$=\sqrt{\left (5+\dfrac{71}{25}\right )\times \dfrac{169\times 10}{16\times 1000}}\times 100$

$=\sqrt{\left (\dfrac{125+71}{25}\right )\times \dfrac{169}{16\times 100}}\times 100$

$=\sqrt{\left (\dfrac{196}{25}\right )\times \dfrac{169}{16\times 100}}\times 100$

$=\dfrac{14}{5}\times \dfrac{13}{4\times 10}\times 100$

$=\dfrac{91}{100}\times 100$

$=91$

Evaluate and state true or false 

$\displaystyle \sqrt{1\frac{4}{5}\,\times\, 14\frac{21}{44}\, \times\, 2\frac{7}{55}}$ is $\displaystyle7\frac{49}{110}$

  1. True

  2. False


Correct Option: A
Explanation:

   $\sqrt { 1\frac { 4 }{ 5 } \times 14\frac { 21 }{ 44 } \times 2\frac { 7 }{ 55 }  }$
$=\sqrt { \frac { 9 }{ 5 } \times \frac { 637 }{ 44 } \times \frac { 117 }{ 55 }  } $
$=\sqrt { \frac { 3^ 2 }{ 5 } \times \frac { 7^ 2\times 13 }{ 11\times 4 } \times \frac { 13\times 9 }{ 11\times 5 }  } $
$=\sqrt { \frac { 3^ 4\times 7^ 2\times 13^ 2 }{ 5^ 2\times 11^ 2\times 2^ 2 }  }$
$=\frac { 3^ 2\times 7\times 13 }{ 5\times 11\times 2 }$
$=\frac{819}{110}$
$=7\frac{49}{110}$

Evaluate: $\sqrt{100}+\sqrt{49}$.

  1. $\sqrt{149}$

  2. $\sqrt{490}$

  3. $\sqrt{10}+\sqrt{14}$

  4. $17$


Correct Option: D
Explanation:

$\sqrt{100}+\sqrt{49}= 10 + 7 = 17.$

Thus the correct option is D.

The square root of $42\, \displaystyle \frac{583}{1369}$ is :

  1. $6\, \displaystyle \frac{19}{37}$

  2. $4\, \displaystyle \frac{2}{11}$

  3. $7\, \displaystyle \frac{2}{121}$

  4. None of these


Correct Option: A
Explanation:

$\sqrt{42\, \displaystyle \cfrac{583}{1369}}\, =\, \sqrt{\displaystyle \cfrac{58081}{1369}}$
$=\, \displaystyle \cfrac{\sqrt{58081}}{\sqrt{1369}}$
$=\, \displaystyle \cfrac{241}{37}\, =\, 6\, \displaystyle \cfrac{19}{37}$

Evaluate $\sqrt{41-\sqrt{21+\sqrt{19-\sqrt{9}}}}$

  1. $3$

  2. $5$

  3. $6$

  4. $6.4$


Correct Option: C
Explanation:

$\sqrt{41-\sqrt{21+\sqrt{19-\sqrt{9}}}}\=\sqrt{41-\sqrt{21+\sqrt{19-3}}}\=\sqrt{41-\sqrt{21+\sqrt{16}}}\=\sqrt{41-\sqrt{21+4}}\=\sqrt{41-\sqrt{25}}\=\sqrt{41-5}=\sqrt{36}=6$

Evaluate  $\sqrt {\displaystyle \frac { 25 }{ 81 } -\displaystyle\frac { 1 }{ 9 }  } $

  1. $\displaystyle \frac { 16}{ 81 }$

  2. $\displaystyle \frac { 25}{ 81 }$

  3. $\displaystyle \frac { 4}{ 9}$

  4. $\displaystyle \frac { 2}{ 3}$


Correct Option: C
Explanation:

$\sqrt {\displaystyle \frac { 25 }{ 81 } -\displaystyle\frac { 1 }{ 9 }  } =\sqrt { \displaystyle\frac { 25-9 }{ 81 }  } =\sqrt {\displaystyle \frac { 16 }{ 81 }  } =\displaystyle\frac { \sqrt { 16 }  }{ \sqrt { 81 }  } =\displaystyle\frac { 4 }{ 9 } $

The sum of the squares of $2$ numbers is $156$. If the one number is $5$, the square of the other number is

  1. $81$

  2. $131$

  3. $11$

  4. $123$


Correct Option: B
Explanation:
Let the two numbers be $x$ and $y$.
$x^{2}$ $+$ $y^{2}$ $\rightarrow$ $156$
${x}$ $\rightarrow$ 5
$x$ $\rightarrow$ $5\times5$ $\rightarrow$ $25$
Substituting, $25$ $+$ $y^{2}$ $\rightarrow$ $156$
 $y^{2}$ $\rightarrow$ $156-25$ $\rightarrow$ $131$

If $\sqrt{49}=7$, then find the value of $\sqrt{49}+\sqrt{0.49}+\sqrt{0.0049}+\sqrt{0.000049}$

  1. 7777

  2. 77.77

  3. 777.7

  4. 7.777


Correct Option: D
Explanation:

$\sqrt{49}+\sqrt{0.49}+\sqrt{0.0049}+\sqrt{0.000049}\=7+\sqrt { \displaystyle\frac { 49 }{ 100 }  } +\sqrt {\displaystyle \frac { 49 }{ 10000 }  } +\sqrt { \displaystyle\frac { 49 }{ 1000000 }  } \ =7+\displaystyle\frac { \sqrt { 49 }  }{ \sqrt { 100 }  } +\displaystyle\frac { \sqrt { 49 }  }{ \sqrt { 10000 }  } +\displaystyle\frac { \sqrt { 49 }  }{ \sqrt { 1000000 }  } \ =7+\displaystyle\frac { 7 }{ 10 } +\displaystyle\frac { 7 }{ 100 } +\displaystyle\frac { 7 }{ 1000 } \ =7+0.7+0.07+0.007\ =7.777$

$\sqrt { \sqrt { 169 } +\sqrt [ 3 ]{ 1728 }  } $ equals

  1. 12

  2. 5

  3. 3

  4. 9


Correct Option: B
Explanation:

$\sqrt{169}$ $\rightarrow$ $13$

$\sqrt[3]{1728}$ $\rightarrow$ $12$
$12$ $+$ $13$ $\rightarrow$ $25$
$\sqrt{25}$ $\rightarrow$ $5$
Hence, Option B is correct.

169+17283

What is the square root of ${0.000441}$ ?

  1. $0.021$

  2. $0.0021$

  3. $0.21$

  4. $2.1$


Correct Option: A
Explanation:

$\sqrt{0.000441}$


$\sqrt{441}$ $\rightarrow$ $21$

$\sqrt{1000000}$ $\rightarrow$ $1000$

$\sqrt{0.000441}$ $\rightarrow$ $\sqrt{441}$ $/$ $\sqrt{1000000}$

$\sqrt{0.000441}$ $\rightarrow$ $\dfrac{21}{1000}$ $\rightarrow$ $0.021$

Hence, Option A is correct.

If x is a positive integer less than 100, then the number of x which make $\displaystyle \sqrt{1+2+3+4+x}$ an integer is

  1. 6

  2. 7

  3. 8

  4. 9


Correct Option: B
Explanation:

Let, $\sqrt{1+2+3+4+5+x}=l$, where $ l $ is an positive integer.
$\Rightarrow \sqrt{10+x}=l$
$\Rightarrow 10+x=l^2$
$\Rightarrow x=l^2-10$
Given, $1<x<100$
$\Rightarrow 1<l^2-10<100$
$\Rightarrow 11<l^2<110$
$\Rightarrow \sqrt{11}<l<\sqrt{110}$
$\Rightarrow 3.32<l<10.49$
$\Rightarrow l=4,5,6,7,8,9,10$              ($\because l\text{ is an integer.}$)
Therefore, there are 7 values of $x$.

The least number by which 176 be multiplied to make the result a perfect square, is:

  1. 8

  2. 9

  3. 10

  4. 11


Correct Option: D
Explanation:
$176 = \underline {2 \times 2} \times \underline {2 \times 2} \times 11.$
So, in order to make it a perfect square, it must be multiplied by 11.

Find the square roots of $100\;and\;169$ by method of repeated substraction.

  1. $10; 13$

  2. $10; 17$

  3. $20; 13$

  4. $20; 17$


Correct Option: A
Explanation:

For $\sqrt{100}$
$100-1=99$
$99-3=96$
$96-5=91$
$91-7=84$
$84-9=75$
$75-11=64$
$64-13=51$
$51-15=36$
$36-17=29$
$19-19=0$

For $\sqrt{169}$
$169-1=168$
$168-3=165$
$165-5=160$
$160-7=153$
$153-9=144$
$144-11=133$
$133-13=120$
$120-15=105$
$105-17=88$
$88-19=69$
$69-21=48$
$48-23=25$
$25-25=0$

From $100\;and\;169$ we have substracted successive odd numbers starting from $1$ and obtained $0$ at $10th\;and\;13th$ steps, respectively.
So, $\sqrt{100}=10\;and\;\sqrt{169}=13$. 

The least number which must be subtracted from 6,156 to make it a perfect square is:

  1. 62

  2. 72

  3. 52

  4. 82


Correct Option: B
Explanation:
First we will find the square root of $6156$:

$\sqrt { 6156 } =\sqrt { 2×2×3×3×3×3×19 } =2×3×3×\sqrt { 19 } =18×4.358=78.444...$

Now, we find the square of $78$ as follows:

${ 78 }^{ 2 }=78×78=6084$

Let us now subtract $6156$ from $6084$ as shown below:

$6156 - 6084 = 72$

Hence, $72$ will be subtracted from $6156$ to make it a perfect square.

$\displaystyle {\sqrt{\frac{36.1}{102.4}}}\, =\, ?$

  1. $\displaystyle \frac{29}{32}$

  2. $\displaystyle \frac{19}{72}$

  3. $\displaystyle \frac{19}{32}$

  4. $\displaystyle \frac{29}{62}$


Correct Option: C
Explanation:

$\displaystyle {\sqrt {\frac{36.1}{102.4}}\, =\, \sqrt {\frac{361}{1024}} = \frac{19}{32}}$

Find the square root of $100$ by the method of repeated substraction.

  1. $10$.

  2. $11$

  3. $9$

  4. $12$


Correct Option: A
Explanation:

We know that the sum of the first n odd natural numbers is $n^{2}$
From $100$, we subtract successive odd numbers starting from $1$ as under
$100-1=99\;\;\;99-3=96$
$96-5=91\;\;\;\;91-7=84$
$84-9=75\;\;\;\;75-11=64$
$64-13=51\;\;\;51-15=36$
$36-17=19\;\;\;19-19=0$
and obtain $0$ at $10th$ step.
$\therefore\;\sqrt{100}=10$.
From $169$, we subtract successive odd numbers starting from $1$ as under
$169-1=168\;\;\;168-3=165$
$165-5=160\;\;\;\;160-7=153$
$153-9=144\;\;\;\;144-11=133$
$133-13=120\;\;\;120-15=105$
$105-17=88\;\;\;88-19=69$
$69-21=48\;\;\;48-23=25$
$25-25=0$
and obtain $0$ at $13th$ step.
$\therefore\;\sqrt{169}=13$.





The value of $\sqrt{1\displaystyle\frac{1}{2}-\begin{bmatrix}1\displaystyle\frac{1}{2}-1\displaystyle\frac{1}{2}+\begin{pmatrix}1\displaystyle\frac{1}{2}-1\displaystyle\frac{1}{2}-1\displaystyle\frac{1}{4}\end{pmatrix}\end{bmatrix}}$ is

  1. $\displaystyle\frac{1}{2}$

  2. $\displaystyle\frac{1}{4}$

  3. $\displaystyle\frac{1}{16}$

  4. $1\displaystyle\frac{1}{5}$


Correct Option: A
Explanation:

$\sqrt{1\displaystyle\frac{1}{2}-\begin{bmatrix}1\displaystyle\frac{1}{2}-1\displaystyle\frac{1}{2}+\begin{pmatrix}1\displaystyle\frac{1}{2}-1\displaystyle\frac{1}{2}-1\displaystyle\frac{1}{4}\end{pmatrix}\end{bmatrix}}$
$\Rightarrow \sqrt{\frac{3}{2}-\left [ \frac{3}{2}-\frac{3}{2}+\left ( \frac{3}{2}-\frac{3}{2}-\frac{5}{4} \right ) \right ]}$
$\Rightarrow \sqrt{\frac{3}{2}-\left [ 0+\left ( \frac{6-6-5}{4} \right ) \right ]}$
$\Rightarrow \sqrt{\frac{3}{2}-\frac{5}{4}}$
$\Rightarrow \sqrt{\frac{6 -5}{4}}$
$\Rightarrow \sqrt{\frac{1}{4}}$
$\Rightarrow \frac{1}{2}$




If $\sqrt{1\, +\, \displaystyle \frac{27}{169}}\, =\, 1\, +\, \displaystyle \frac{x}{13}$, then the value of $x$ is

  1. 1

  2. 14

  3. Cannot be determined

  4. None of these


Correct Option: A
Explanation:

$\sqrt{1\, +\, \displaystyle \cfrac{27}{169}}\, =\, \displaystyle \cfrac{196}{169}\, =\, \displaystyle \cfrac{14}{13}$
$\Rightarrow 1\, \displaystyle \cfrac{1}{13}\, =\, 1\, +\, \displaystyle \cfrac{1}{13}$
$\therefore\, x\, =\, 1$

Simplify the expression involving rational exponents:
${ \left( \displaystyle\frac { 25 }{ 64 }  \right)  }^{ { 1 }/{ 2 } }$

  1. $\displaystyle\frac { 25 }{ 8 } $

  2. Not a real number

  3. $\displaystyle\frac { 5 }{ 8 } $

  4. $\displaystyle\frac { 5 }{ 64 } $


Correct Option: C
Explanation:

$\left(\dfrac{25}{64}\right)^\frac{1}{2}$ = $\left(\dfrac{5^2}{8^2}\right)^\frac{1}{2}$ = $\dfrac{5}{8}$

If $n = \sqrt {\dfrac {16}{81}}$, what is the value of $\sqrt {n}$?

  1. $\dfrac {1}{9}$

  2. $\dfrac {1}{4}$

  3. $\dfrac {4}{9}$

  4. $\dfrac {2}{3}$

  5. $\dfrac {9}{2}$


Correct Option: D
Explanation:

Since $n = \sqrt {\dfrac {16}{81}} = \dfrac {4}{9}$, 
then $\sqrt {n} = \sqrt {\dfrac {4}{9}} = \dfrac {2}{3}$.

The correct answer is D.

Find the square root of decimal 5.76.

  1. $4.2$

  2. $2.4$

  3. $18.4$

  4. $4.23$


Correct Option: B
Explanation:

$576=2^{6} \times 3^{6}=(2^{3} \times3)^2=(24)^{2}$

$100=2^{2} \times 5^{2}=(2 \times5)^{2}=(10)^{2}$
$\sqrt{5.76}=\sqrt{\dfrac{576}{100}}$=$\sqrt{({\dfrac{24}{10}})^{2}}$
$=\dfrac{24}{10}=2.4$

The square root of $144$ is 

  1. $114$

  2. $442$

  3. $12$

  4. $24$


Correct Option: C
Explanation:

$144 = 2\times2\times2\times2\times 3\times3$

$\sqrt{144} = \sqrt{2\times2\times2\times2\times 3\times3}=2\times2\times3=12$

Find the square root of $81$.

  1. $9$

  2. $45$

  3. $18$

  4. $81$


Correct Option: A
Explanation:

$ 81 = 3\times3\times3\times3$

$\sqrt{ 81} = \sqrt{3\times3\times3\times3}=3\times3=9$

Complete the repeated subtraction to find the square root of $225$.

  1. $9$

  2. $45$

  3. $25$

  4. $15$


Correct Option: D
Explanation:

$225 -1 = 224$ ,

$224 -3 = 221 $,
$221-  5 = 216$, 
$216 -7 = 209$,
$209 - 9= 200$ ,
$200 -11 = 189$
$189-  13 = 176$ , 
$176-  15 = 161$, 
$161 -17 = 144$,
$144- 19 = 125$
$125 - 21 = 104 $
$ 104-  23 = 81 $
$81-  25 = 56$
$ 56-  27 = 29$, 
$29 -29 = 0 = 15$ 
Therefore, D is the correct answer.

Simplify the following : $\sqrt { 0.0081 } $

  1. $0.02$

  2. $0.09$

  3. $0.06$

  4. $0.05$


Correct Option: B
Explanation:
$0.09$: Since $(0.09)(0.09)=0.0081$, 

$\sqrt{0.0081}=0.09$. 

You can also rewrite $0.0081$ as $81\times {10}^{-4}$

$\sqrt { 81\times { 10 }^{ -4 } } =\sqrt { 81 } \times \sqrt { { 10 }^{ -4 } } =9\times { \left( { 10 }^{ -4 } \right)  }^{ \frac { 1 }{ 2 }  }=9\times { 10 }^{ -2 }=0.09$

Which of the following is the value of $\displaystyle \sqrt { \sqrt [ 3 ]{ 0.000064 }  } $ ?

  1. $0.004$

  2. $0.008$

  3. $0.02$

  4. $0.04$

  5. $0.2$


Correct Option: E
Explanation:

$\sqrt[3]{0.000064}$$=$$0.04$

$\sqrt{0.04}$$=$$0.2$
 $\therefore \displaystyle \sqrt { \sqrt [ 3 ]{ 0.000064 }  } =0.2$
Hence, Option E is correct.

What is the value of $\sqrt{\frac{400}{25}}$?

  1. 4

  2. 3

  3. 2

  4. 1


Correct Option: A
Explanation:

$\sqrt{\dfrac{400}{25}}$
= $\dfrac{20}{5} = 4$.

Find the value of $\sqrt{\frac{484}{121}}$

  1. 4

  2. 3

  3. 2

  4. 1


Correct Option: C
Explanation:

$\sqrt{\dfrac{484}{121}}$
= $\dfrac{22}{11}$
= 2

Find the square root of 841.

  1. 21

  2. 28

  3. 29

  4. 25


Correct Option: C
Explanation:

$\sqrt{841}= \sqrt{29 \times 29}$
So, the square root of 841 is 29.

Subtracting which odd number will get the value of 288 for the square root of the number 484 using repeated subtraction method?

  1. 25

  2. 23

  3. 27

  4. 29


Correct Option: C
Explanation:

Repeated subtraction method: Subtract successive odd numbers from the given number starting from 1 till the difference becomes zero.
So, 484 - 1 = 483
483 - 3 = 480
480 - 5 = 475
475 - 7 = 468
468 - 9 = 459
459 - 11 = 448
448 - 13 = 435
435 - 15 = 420
420 - 17 = 403
403 - 19 = 384
384 - 21 = 363
363 - 23 = 340
340 - 25 = 315
315 - 27 = 288 
27 is the odd number, subtracting with 315 to get the value of 288.

From which odd number you will get the value zero, for the square root of the number 64 using repeated subtracting method?

  1. 13

  2. 15

  3. 9

  4. 5


Correct Option: B
Explanation:

Repeated subtraction method: Subtract successive odd numbers from the given number starting from 1 till the difference becomes zero.
So, 64 - 1 = 63
63 - 3 = 60
60 - 5 = 55
55 - 7 = 48
48 - 9 = 39
39 - 11 = 28
28 - 13 = 15
15 - 15 = 0.
15 is the odd number, we get the value of zero for the square root of the number 64.

Calculate the value of $\sqrt{\frac{144}{256}}$.

  1. 0.55

  2. 0.75

  3. 0.65

  4. 0.45


Correct Option: B
Explanation:

$\sqrt{\dfrac{144}{256}}$
= $\dfrac{12}{16}$.
= 0.75

Find the square root of 1369.

  1. 31

  2. 33

  3. 36

  4. 37


Correct Option: D
Explanation:

$\sqrt{1369}= \sqrt{37 \times 37}$
So, the square root of 1369 is 37.

Subtracting which odd number will get the value of 144 for the square root of the number 169 using repeated subtraction method?

  1. 3

  2. 5

  3. 7

  4. 9


Correct Option: D
Explanation:

Repeated subtraction method: Subtract successive odd numbers from the given number starting from 1 till the difference becomes zero.
So, 169 - 1 = 168
168 - 3 = 165
165 - 5 = 160
160 - 7 = 153
153 - 9 = 144
9 is the odd number, subtracting with 153 to get the value of 144.

Evaluate: $\sqrt{\frac{784}{196}}$

  1. 5

  2. 4

  3. 3

  4. 2


Correct Option: D
Explanation:

$\sqrt{\dfrac{784}{196}}$
= $\dfrac{28}{14} = 2$.

If $x=5+2\sqrt { 6 } $, then $\sqrt{ x }+\dfrac{1}{\sqrt { x }} $ is ?

  1. $2\sqrt{ 2 } $

  2. $2\sqrt { 3 } $

  3. $\sqrt { 3 } +\sqrt { 2 } $

  4. $\sqrt { 3 } -\sqrt { 2 } $


Correct Option: A
Explanation:

Let $A=\sqrt { x } +\cfrac { 1 }{ \sqrt { x }  } $
$\Rightarrow { A }^{ 2 }=x+\cfrac { 1 }{ x } -2=\left( 5+2\sqrt { 6 }  \right) +\cfrac { 1 }{ 5+2\sqrt { 6 }  } -2$
$=5+2\sqrt { 6 } +\cfrac { 5-2\sqrt { 6 }  }{ 25-24 } -2=8$ $\text{[Rationalising the denominator]}$
$=5+2\sqrt { 6 } + { 5-2\sqrt { 6 }  } -2=8$
$ \Rightarrow A^2=8 $
$ \Rightarrow A=2\sqrt { 2 } $

If $a,b,c$ are three distinct positive real numbers then the number of real roots of $ax^2+2b|x|-c=0$ is

  1. $0$

  2. $2$

  3. $4$

  4. none of these


Correct Option: B
Explanation:

${ ax }^{ 2 }+2b{ |x| }-c=a{ |x| }^{ 2 }+2b|x|-c$

                       $|x| =\dfrac { -b\pm \sqrt { 4{ b }^{ 2 }+4ac }  }{ 2a }$
                             $=\dfrac { -2b\pm 2\sqrt { { b }^{ 2 }+ac }  }{ 2a }$
                             $=\dfrac { -b\pm \sqrt { { b }^{ 2 }+ac }  }{ a }$
                             $=\dfrac { -b+\sqrt { { b }^{ 2 }+ac }  }{ a }$ (|x| can't be negative)
$\therefore 2$ real roots                            

A group of people decided to collect as many rupees from each member of the group as is the number of members. If the total collection amounts to $2209$, what is the number of members in the group?

  1. $37$

  2. $47$

  3. $107$

  4. $43$


Correct Option: B
Explanation:

Rupee collected from each member $=$ number of member in group $=$ $k$

$k\times k$ $=$ $2209$
$k=$ $\sqrt{2209}$
$k=$ $47$
Hence, Option B is correct.

For what value of $\displaystyle x+\frac { 1 }{ 4 } \sqrt { x } +{ a }^{ 2 }$ will be perfect square -

  1. $\displaystyle \pm { 1 }/{ 18 }$

  2. $\displaystyle \pm { 1 }/{ 8 }$

  3. $\displaystyle \pm { 1 }/{ 5 }$

  4. $\displaystyle { 1 }/4$


Correct Option: B
Explanation:

If $\displaystyle x+\frac { 1 }{ 4 } \sqrt { x } +{ a }^{ 2 }$ is a perfect square
then $\displaystyle \frac { 1 }{ 4 } \sqrt { x } =2\times \sqrt { x } \times \left( \pm a \right) $
$\displaystyle \therefore \quad a=\pm \frac { 1 }{ 8 } $

Solve:
$ \sqrt { 225 } -x=0 ,x=?$
  1. $10$

  2. $4$

  3. $15$

  4. $5$


Correct Option: C
Explanation:
$\sqrt { 225 } =15$
$\sqrt { 225 } -x=0$
$15-x=0$
$x=15$


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