A) \[10(1+\sqrt{2})m\]
B) \[10\left( 1+\frac{\sqrt{3}}{2} \right)m\]
C) 15 m
D) 20 m
Correct Answer: A
Solution :
Let AB is a tree of height n and\[QC=BC\] In \[\Delta ADC,\cos 45{}^\circ =\frac{DA}{DC}\] \[\Rightarrow \] \[\frac{1}{\sqrt{2}}=\frac{10}{DC}\] \[\Rightarrow \] \[DC=10\sqrt{2}\] and \[AC=DC\sin 45{}^\circ =10\sqrt{2}.\frac{1}{\sqrt{2}}=10\] Hence, height of the tree, \[n=AC+DC\] \[=10+10\sqrt{2}\] \[=10(1+\sqrt{2})m\]You need to login to perform this action.
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