Q. 20

If a 1.5 m tall girl stands at a distance of 3 m from a lamp-post and casts a shadow of length 4.5 m on the ground, then the height of the lamp-post is
A. 1.5 m

B. 2 m

C. 2.5 m

D. 2.8 m

Answer :

Let AB be the tower of h meters and CD be the girl of 1.6m height casting shadow = DE of 4.8 m, standing at the distance of 3.2m from the tower.


tan CED = CD/ DE = ………………….1

tan CED = 1/3


tan CED = = ………………….2

From 1 and 2


h = m

h = 2.5m

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