A) 100 ft
B) 120 ft
C) 150 ft
D) None of these
Correct Answer: B
Solution :
Obviously, from figure \[\tan \alpha =\frac{h/3}{40}=\frac{h}{120}\] .....(i) \[\tan \beta =\frac{h}{40}=\frac{3h}{120}\] .....(ii) Therefore \[\tan \theta =\tan (\beta -\alpha )\] \[\Rightarrow \] \[\frac{1}{2}=\frac{\frac{3h}{120}-\frac{h}{120}}{1+\frac{3{{h}^{2}}}{14400}}\Rightarrow h=120,\,40\] But \[h=40\] cannot be taken according to the condition, therefore\[h=120ft\].You need to login to perform this action.
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