Tag: construction of angles

Questions Related to construction of angles

At 5'O clock the angle between two hands in a clock is 

  1. ${ 120 }^{ \circ }$

  2. ${ 130 }^{ \circ }$

  3. ${ 140 }^{ \circ }$

  4. ${ 150 }^{ \circ }$


Correct Option: D
Explanation:
A clock has $12$ equal parts$={360}^{\circ}$
$1$ part$=\dfrac{{360}^{\circ}}{12}={30}^{\circ}$
At $5$O clock the hands will be between $12$ and $5=5$parts
$\therefore 5$ parts$=5\times{30}^{\circ}={150}^{\circ}$

The centre of a clock is taken as origin At 4.30 pm the equation of line along minute hand is x = 0 Therefore at this istant the equation of line along the hour hand will be 

  1. $x - y = 0$

  2. $x + y = 0$

  3. $\displaystyle y=\sqrt{2x}$

  4. $\displaystyle y=\frac{x}{\sqrt{2}}$


Correct Option: B
Explanation:

The centre of a clock is taken as origin. At 4:30 pm equation of line along minute hand is $x=0$.
Therefore at this instant the equation of line along the hour hand will be 
$m=-1$ ( as tan 135=-1 )
Therefore equation of line y=mx
or $y=-x$
$y+x=0$.

At 4.24 pm, how many degrees has the hour hand of a clock moved from its position at noon?

  1. $132^\circ$

  2. $135^\circ$

  3. $140^\circ$

  4. $145^\circ$


Correct Option: A
Explanation:

From noon 12 noon to 4:24 total minutes
4*60+24
=240+24
=264
Now in 12 hour angle made by the hour hand= $={ 360^0 } $
so in 1 minute angle made by the hour hand=360/12*60=$= { \frac { 1 }{ 2 }  } $
so in 264 minute angle made by the hour hand=$=264\times \frac { 1 }{ 2 } ={ 132^0 } $

The minute hand of a clock is 14 cm long
How much distance dose the end of the minute hand
travel in 15 minutes?$\displaystyle \left ( Take \pi  =\frac{22}{7}\right )$

  1. 11 cm

  2. 22 cm

  3. 33 cm

  4. 44 cm


Correct Option: B
Explanation:

Given minute hand of clock is 14 cm long

Then distance traveled by minute hand in 15 minutes
= one forth of circumference of circle radius 14 cm
=$\left ( \frac{1}{4}\times 2\times \frac{22}{7}\times 14 \right )=22 cm$

At 5:20 the angle formed between the two hands of a clock is

  1. obtuse

  2. right

  3. acute

  4. none of these


Correct Option: C
Explanation:

A clock is a circle, and a circle always contains $360^o$. Since there are 


$60$ minutes on a clock, each minute mark is $6^o.$

$\Rightarrow$  $\dfrac{360^o}{60}=6\,degree$
The minute hand on the clock will point at $20$ minutes, allowing us to calculate it's position on the circle.

$\Rightarrow$  $20\,minutes\times 6=120\,degree$
So the angle made by the hour hand in $5$ hours $20$ minutes $= 5\dfrac{1}{3}hours$ 
                                                                                                    $=\dfrac{16}{3}\times\dfrac {360^o}{12}$ 
                                                                                                    $=160^o$

Hence angle between the hour hand and minute hand at $5:20=160^o-120^o=40^o$

$\therefore$  $40^o$ is less than $90^o$ means its acute angle.

$\therefore$   At $5:20$ the angle formed between the two hands of a clock is $acute.$

At 3 o'clock, the angle formed between the two hands of a clock is

  1. right

  2. acute

  3. obtuse

  4. left


Correct Option: A
Explanation:

$\Rightarrow$  A clock is a circle made of $360^o$. and that 

$\Rightarrow$  Each number represents an angle and the separation between them is $\dfrac{360}{12}=30^o$. 
$\Rightarrow$  At $2:00$, the minute hand is on the $12$ and the hour hand is on the $3$.  
$\Rightarrow$  The angle between two hands $=3\times 30^o=90^o$
$\Rightarrow$  At $3$ o'clock, the angle formed between the two hands of a clock is $right\,angle.$

At 9 o'clock the formed between the hands of a clock is

  1. complete angle

  2. reflex angle

  3. zero angle

  4. none


Correct Option: D
Explanation:

At 9:00 the angle formed between the hands of a clock is a right angle..

At 3 o'clock the angle formed between the hands of a clock is

  1. reflex angle

  2. right angle

  3. straight angle

  4. acute angle


Correct Option: B
Explanation:

At 3:00 the angle formed between the hands of clock is right angle..

Type of angle between the hands of a clock when the time is 5:20 is

  1. right angle

  2. straight angle

  3. obtuse angle

  4. acute angle


Correct Option: D
Explanation:

It will form an acute angle..

An angle which measures $\displaystyle 180^{0}$  is called a

  1. straight angle

  2. obtuse angle

  3. right angle

  4. complete angle


Correct Option: A
Explanation:

Straight angle is a angle which measures 180 degrees..