sir this is the important question from the book -ML aggarwal( avichal publication) class 10th , chapter20 , heights and distances
The angle of elevation of the top of an unfinished tower
at a point distant 120 m from its base is 45.
How much higher must the tower be raised
so that its angle of elevation at the same point may be 60?
question no 36 , heights and distances , ICSE board, ML Aggarwal