Tag: maths

Questions Related to maths

Area bounded by $y|y|-x|x|=1,\ y|y|+x|x|=1$ and $y=|x|$ is

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

  2. ${\pi}$

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

  4. $None\ of\ these$


Correct Option: A

A farmer wishes to cultivate four different crops in equal areas in his $1$ car of land.. The land he should allocate for each crop is:  

  1. $10\ m^{2}$

  2. $25\ m^{2}$

  3. $75\ m^{2}$

  4. $100\ m^{2}$


Correct Option: A

A room is x meters long, y meters broad, and z meters high; find how many square meters of carpet will be required for the floor and how many square meters of paper for the walls?

  1. xy and 2xy + 2yz

  2. xy and 2xz + 2yz

  3. xy and 2xy

  4. xy and 2xy + 2xz


Correct Option: B
Explanation:

$Length = x, breadth = y$
Area of the floor $= xy m^2$
Area of four walls $= 2h(l + b) = 2z (x +y) = 2zx + 2yz$

Find the area of a square inscribed in a circle of radius $\displaystyle 5\sqrt{2}$ cm (in $\displaystyle cm^{2}$)

  1. 75

  2. 100

  3. 125

  4. 150


Correct Option: B
Explanation:

The diagonal of the square will be equal to the diameter of the circle.
So,diagonal of the square $ = 2 \times 5 \sqrt {2} = 10 \sqrt {2} $

Diagonal of a square $ = \sqrt {2} \times side $
So, $ 10 \sqrt {2} = \sqrt {2} \times side $
$ => Side  =  10  cm $

Area of the square $ = { side }^{ 2 } = { 10 }^{ 2 } = 100 $ sq cm

What is the maximum area of a four-sided plane with a perimeter of $12$ inches?

  1. $8$ square inches

  2. $10$ square inches

  3. $6$ square inches

  4. $9$ square inches


Correct Option: D
Explanation:

The area is maximum when the four-sided plane is a square.

The perimeter of a square $ = 4 \times$ side $= 12 $ inches
$ \Rightarrow$ side $= 3  $ inches

Now, area of the square $ =$ side $\times$ side $= 3 \times 3 = 9 $ square inches.

Calculate area of the shape obtained by joining an equilateral triangle to one of the end of rectangle and a semicircle to the other end of rectangle. The sides of equilateral triangle is $3$ cm and one of the sides of rectangle is $4$ cm.

  1. $28.12\ cm^{2}$

  2. $30.02\ cm^{2}$

  3. $35.02\ cm^{2}$

  4. $40.02\ cm^{2}$


Correct Option: B

Consider a rectangle of perimeter $24\ cm$ with sides $a$ and $b$. Then the total number of square grids formed in that rectangle is given by

  1. $a\times b$

  2. $a+b$

  3. $a-b$

  4. $\dfrac{a}{b}$


Correct Option: A
Explanation:
Area of rectangle$=a\times b$
Area of $1$ square grid$=1 cm^2$
No. of square grids$=\cfrac { a\times b }{ 1 } =a\times b$

Form a rectangle with $8$ square grids where each square grid measure $1\ cm^{2}$. Find the total area of the rectangle.

  1. $8\ cm^{2}$

  2. $12\ cm^{2}$

  3. $16\ cm^{2}$

  4. $20\ cm^{2}$


Correct Option: A
Explanation:

Area of rectangle$=8\times $ area of $1$ square grid$=8\times 1=8 cm^2$

Let there be a rectangle of area $24\ cm^{2}$. Then find the total number of square grids made in this rectangle.(Each square grid measures $1\ cm^{2}$)

  1. $3$

  2. $6$

  3. $12$

  4. $24$


Correct Option: D
Explanation:

Number of square grids$=\cfrac { Area\quad of\quad rectangle }{ area\quad of\quad square\quad grid } =\cfrac { 24 }{ 1 } =24$

Three coins of the same size (radius $1cm$) are placed on table such that each of them touches the other two. The area enclosed by the coins is:

  1. $\left( \cfrac { \pi }{ 2 } -\sqrt { 3 } \right) { cm }^{ 2 }$

  2. $\left( \sqrt { 3 } -\cfrac { \pi }{ 2 } \right) { cm }^{ 2 }$

  3. $\left(2 \sqrt { 3 } -\cfrac { \pi }{ 2 } \right) { cm }^{ 2 }$

  4. $\left(3 \sqrt { 3 } -\cfrac { \pi }{ 2 } \right) { cm }^{ 2 }$


Correct Option: B
Explanation:

Radius of each coin $=1\ cm$

With all the three centres an equilateral triangle of side 2 cm is formed.
Area enclosed by coind $=$ Area of equilateral triangle $-3\times$ Area of sector of angle $60^{o}$
                                         $=\dfrac{\sqrt3}{2}(2)^2-3\times\dfrac{60}{360}\times\pi(1)^2$
                                         $=\dfrac{\sqrt3}{4}\times4-3\times\dfrac{1}{6}\times\pi$
                                          $=\left(\sqrt3-\dfrac{\pi}{2}\right)\ cm^2$