On walking 100 metres towards a building in a horizontal line, the angle of elevation of its top changes from 45° to 60°. What will be the height (in metres) of the building?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 50(3 + √3)
Let Ab be the height h of the building
In △ABC
tan60° = h/x
x = h/√3
In △ABD
tan45° = h/x + 100
h/√3 + 100 = h
h = 100√3/(√3 - 1) = 50(3 + √3)