Q31 of 68 Page 9

An observer standing at a distance of 72 m from a building measures the angles of elevation of the top and foot of a flagstaff on the building as 54° and 50°. Find the height of the flagstaff. [tan54° = 1.376, tan50° = 1.192]

31


From the ∆ABC,





From the ∆DBC,





Now, the length of the flagstaff = AB – DB


=99.07 – 85.82


=13.25


Therefore, the length of the flagstaff is 13.25 m.


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A man who is tall sees that angle of elevation of the top of a temple is 30°. If the distance of the man from the temple is 15 m, find the height of the temple.

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A flagstaff stands on a tower. At a point distant 60 m from the base of the tower, the top of the flagstaff makes an angle of 60° and the tower makes an angle of 30° at that very point. Find the height of the flagstaff