Q7 of 28 Page 93

The angles of elevation of the top of a tower from two points at a distance of a m and b m (a > b) from the base of the tower and in the same straight line with it are respectively 30° and 60°. Then height of the tower is


Let height of the tower AC = g.


Given, AD = b, AB = a. ∠ABC = 30o∠ADC = 60


We know that, tan θ


in ∆ABC,





……….(1)


in ADC,





g = b√3 …………..(2)


Multiplying Equation (1) and (2)


g2 = ab


g = √(ab)

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