A) \[30\left( 1+\frac{1}{\sqrt{3}} \right)m\]
B) \[30\left( 1-\frac{1}{\sqrt{3}} \right)\,\,m\]
C) \[30\left( \sqrt{3}+1 \right)\,\,m\]
D) \[30(\sqrt{3}-1)\,\,m\]
Correct Answer: B
Solution :
Here, AB be the building and CD is the tower. So, AB = 30 m, Let DC = h Then, as DE ||AC so AE = DC = A \[\therefore \] \[BE=(30-h)\,\,m\] Here, \[\cot 45{}^\circ =\frac{AC}{BA}\] (in\[\Delta ABC\]) \[\frac{AC}{30}=1\]\[\Rightarrow \]\[AC=30\,\,m\] Now, in\[\Delta BDE,\]\[\tan 30{}^\circ =\frac{BE}{DE}\] \[\therefore \] \[CD=AE=AB-BE=30-\frac{30}{\sqrt{3}}\] \[h=30\left( 1-\frac{1}{\sqrt{3}} \right)\,\,m\]You need to login to perform this action.
You will be redirected in
3 sec