question_answer

The angle of elevation of a tower from a point A due south of it is 30o and from a point B due west of it is 45o. If the height of the tower be 100 metres, then AB =

A) 150 m

B) 200 m

C) 173.2 m

D) 141.4 m

Correct Answer: B

Solution :

\[OB=100\cot {{45}^{o}}\] \[OA=100\cot {{30}^{o}}\] \[AB=\sqrt{(O{{A}^{2}}+O{{B}^{2}})}\]             \[=200m\].