Q15 of 28 Page 93

The angle of elevation of the top of a pillar from a point situated on a plane in 15°. On walking 100 m towards the pillar the angle of elevation becomes 30°. Then find the height of the pillar. (where, tan 15° = 2√3)


Let Height of the tower is BC = g.


Given, ∠CAB = 15o∠CDB = 30o AD = 100.


in ∆CAB,




………….(1)


in ∆CDB,




………….(2)


Equation (1) – Equation(2)






100 = 2g + g√3 – g√3


100 = 2g


g = 50


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