Question

If the angular diameter of the moon be30', how far from the eye should a coin of diameter 2.2 cm be kept to hide the moon ?

Answer 1

The answer is
252cm
Ok

Answer 2

Answer:

The required distance is 252 cm.

Step-by-step explanation:

Given : If the angular diameter of the moon be 30'.

To find : How far from the eye should a coin of diameter 2.2 cm be kept to hide the moon ?

Solution :

Let the distance be r cm.

If the angular diameter of the moon be $\theta =30'$

In degree, $\theta =\frac{30}{60}^\circ$

Convert angle into radian,

$\theta =\frac{30}{60}\times \frac{\pi}{180}$

$\theta =\frac{\pi}{360}$ in radians.

We have given diameter of coin = 2.2 cm.

So, The length of the arc = 2.2 cm

Applying the length of arc formula,

$l=r\theta$

Substitute the values in the formula,

$2.2=r\times \frac{\pi}{360}$

$r=\frac{2.2\times 360}{\frac{22}{7}}$

$r=\frac{2.2\times 360\times 7}{22}$

$r=252$

Therefore, The required distance is 252 cm.