Tag: maths

Quizzes (518) Questions (9324)

Questions Related to maths

Multiple choice maths square root square root of perfect square finding square root of a number square root of a perfect square

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. $19$
Reveal answer Fill a bubble to check yourself
C Correct answer
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 $18$

Multiple choice maths square root square root of perfect square finding square root of a number square root of a perfect square

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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice maths square root square root of perfect square finding square root of a number square root of a perfect square

Square root of $400$ is?

  1. $40$
  2. $25$
  3. $20$
  4. $100$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$400=2\times 200$

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

Multiple choice maths square root square root of perfect square finding square root of a number square root of a perfect square

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

  1. $2 + \sqrt{7}$
  2. $2 - \sqrt{7}$
  3. $ \sqrt{7} - 2$

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
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,

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