A flag of height 4 metres is standing on the top of a building. The angle of elevation of the top of the flag from a point X is 45° and the angle of elevation of the top of building from X is 30°. Point X is on the ground level. What is the height (in metres) of the building?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 2(√3 + 1)
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Application |
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Suppose the height of the building = H meter So, Tan45 = (H + 4)/XY ⇒ XY = H + 4 And Tan30 = H/XY ⇒ 1/√3 = H/XY ⇒ XY = H√3 So, (H + 4) = H√3 ⇒ H = 4/(√3 – 1) = 2(√3 + 1) meters |
