Q36 of 40 Page 1

If the angle of elevation of a cloud from a point 10 metres above a lake is 30° and the angle of depression of its reflection in the lake is 60°, find the height of the cloud from the surface of lake.

OR


A vertical tower of height 20 m stands on a horizontal plane and is surmounted by a vertical flag - staff of height h. At a point on the plane, the angle of elevation of the bottom and top of the flag staff are 45° and 60° respectively. Find the value of h.


Here, BN → Lake


C → Position of level


Clearly CN = C′N


I-Δ CAM




…(1)


In Δ AMC′



…(2)


From eq. (1) and (2)



h = 10 m


OR


AB → Flag Staff (1 m)


BC → Tower (20 m)


DC → x(8ay)


Diagram


In Δ ADC,




…(1)


In Δ BDC



(2)


Fro, eq. (1) & (2)





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