question_answer

Two poles 15 metres and 30 metres high stand upright in a playground. If their feet be 36 metres apart, find the distance between their tops.

A) 36 m                   

B)          39 m

C) 15 m                   

D)         30 m

E) None of these

Correct Answer: B

Solution :

Explanation Option [b] is correct. Let AL, BM be poles with tops at L and M resp. LA = 15m, MB = 30 m, AB = 36 m. Let LN be parallel to the ground LN = AB = 36 m And      MN=30-15 =15m \[\therefore \,\,LM=\sqrt{3{{6}^{2}}-1{{5}^{2}}}\] \[=\,\,\sqrt{1296+225}=39\,m.\]