Asked by  | 4th Apr, 2008, 02:15: PM

Expert Answer:

let height of lamp post = h

and its distance from center of the road = x

here lamp focus covers a total area within 30o so the horizontal distance which is covered by light of lamp should be 10m

so at 10m distance the angle made by lamp on the boundary point will be 90-30 = 60

so we have tan 45 = h/x

and tan 60 = h/10    => h= 10 tan60 = 103

so l=h=103

Answered by  | 8th Sep, 2008, 07:10: PM

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