question_answer

The angle of elevation of a tower at a point distant \[d\] metres from its base is\[{{30}^{o}}\]. If the tower is \[20\,\,m\] high, then the value of \[d\] is:

A) \[10\sqrt{3}m\]               

B) \[\frac{20}{\sqrt{3}}m\]

C) \[20\sqrt{3}m\]               

D) \[10\,\,m\]

Correct Answer: C

Solution :

In\[\Delta ABC\],                 \[\tan {{30}^{o}}=\frac{BC}{AB}\] \[\Rightarrow \]                    \[\frac{1}{\sqrt{3}}=\frac{20}{d}\] \[\Rightarrow \]               \[d=20\sqrt{3}m\]