The angle of the top of a vertical tower standing on a horizontal plane is observed to be 45 ° from a…

The angle of the top of a vertical tower standing on a horizontal plane is observed to be 45° from a point A on the plane. Let B be the point 30 m vertically above the point A. If the angle of elevation of the top of the tower from B be 30° , then the distance (in m) of the foot of the tower from the point A is:
  1. 153+3
  2. 151+3
  3. 155-3
  4. 153-3

Solution


tan45o=1=x+30y⇒x+30=y ......(i)
tan30o=13=xy⇒x=y3 ......(ii)
from (i) and (ii) y=153+3

Asked in: JEE Main 2019 (12 Apr Shift 2)

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