Trigonometric Equations Question 212

Question: The top of a hill observed from the top and bottom of a building of height h is at the angle of elevation p and q respectively. The height of the hills is

[UPSEAT 2001; EAMCET 1989]

Options:

A) $ \frac{h\cot q}{\cot q-\cot p} $

B) $ \frac{h\cot p}{\cot p-\cot q} $

C) $ \frac{h\tan p}{\tan p-\tan q} $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

  • Let AD be the building of height h and BP be the hill then $ \tan q=\frac{h+x}{y} $ and $ \tan p=\frac{x}{y} $
    Þ $ ,\tan q=\frac{h+x}{x\cot p} $
    $ \Rightarrow x\cot p=(h+x)\cot q $
    Þ $ x=\frac{h\cot q}{\cot p-\cot q} $
    Þ $ h+x=\frac{h\cot p}{\cot p-\cot q} $ .