A) \[36.3m\]
B) \[37.3in\]
C) \[38.3m\]
D) \[39.3in\]
Correct Answer: B
Solution :
[b] \[\tan 15{}^\circ =DE/AE\] |
\[AE=10\,\,cot\,\,15{}^\circ \] ? (1) |
\[\cot (15{}^\circ )=cot(45-30{}^\circ )\] |
\[=\frac{\cot 45{}^\circ \cot 30{}^\circ +1}{\cot 30{}^\circ -\cot 45{}^\circ }\] |
\[\cot 15{}^\circ =\frac{1.\sqrt{3}+1}{\sqrt{3}-1}=2+\sqrt{3}\] |
Putting \[\cot 15{}^\circ \] in eq (1) |
\[AE=10\cot 15{}^\circ \] |
\[=10(2+\sqrt{3})\] |
\[=10(3.73)\] |
\[=37.3m\] |
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