Q30 of 68 Page 9

A flagstaff stands on a vertical tower. At a point distant 10 m from the base of the tower, the tower and the flagstaff make angles 45° and 15° respectively. Find the length of the flagstaff.

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Here, point distance from base pf tower = BC = 10 m


From the ∆ABC,





Now, ∆DBC,





Therefore, the length of flagstaff = AB – DB = 10 – 2.67 = 7.32 m.


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28

A man of height 1 .5 m sees the top of a tree and the angle of elevation of the top at his eye is 60°. Find the height of the tree if the distance of the man from the tree is 36 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.

 31

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]

 32

A 20 m long flagstaff stands on a tower. At a point on the level ground the angles of elevations of the foot and top of the flagstaff are 30° and 60° respectively. Find the height of the tower.