Find the distance from the eye at which a coin of 2 cm diameter should be held so as to conceal the full moon whose angular diameter is 31'.

Explanation

Let, `r` be the distance, at which coin in placed. So that it completely conceals the full moon.


Let, `E` be the eye of the observer. br>

Now, br>


`theta=31^{prime}=(frac{31}{60})^{circ} quad[because quad 60^{prime}=1^{circ}]` br>


Also, br>


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