On a horizontal plane there is a vertical tower with a flag pole on the top of the tower. At a point 9 metres away from the foot of the tower the angle of elevation of the top and bottom of the flag pole are 60° and 30° respectively. Find the height of the tower and the flag pole mounted on it.

Let the height of the Flag-pole = h(m)


And height of tower = (m)



In ∆ABC,


tan 60° =


√3 =


h+ = 9√3 -------(1)


In ∆DBC,


tan 30° =


=


√3 = 9



-------(2)


Now substituting value of in eqn. (1)


h+3√3 = 9√3


h = 9√3-3√3


h = 6√3 m.


Therefore height of tower is 3√3 m. and height of flag pole is 6√3 m.


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