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The angle of elevation and depression of the top and bott...

The angle of elevation and depression of the top and bottom of another building, measured from the top of a 24 m tall building, is 30° and 60°, respectively. Determine the second building's height.

A.

24 m

B.

32\(\sqrt3\) m

C.

24\(\sqrt3\)

D.

32 m

Correct answer is D

The height of the second building H = h + 24

tan θ = \(\frac {opp}{adj}\)

tan 30\(^o = \frac {h}{x}\)

\(\implies\frac{\sqrt 3}{3} = \frac {h}{x}\)

\(\implies x = \sqrt 3 = 3h\)

\(\implies x = \frac {3h}{\sqrt 3}\) ....(i)

tan 60\(^o = \frac {24}{x}\)

\(\implies\sqrt 3 = \frac {24}{x}\)

\(\implies x\sqrt 3 = 24\)

\(\implies x = \frac {24}{\sqrt 3}\) ....(ii)

Equate equation (i) and (ii)

\(\implies \frac {3h}{\sqrt 3} = \frac {24}{\sqrt 3}\)

\(\implies\) 3h = 24

\(\implies h = \frac {24}{3}\) = 8m

∴The height of the second building = 8 + 24 = 32m