One of the most important question from height and distance as it was already asked in previous year paper of 2012 in which we are to find the height of the tower when the angles of depression of the top and bottom of a tower as seen from the top of a 60√3 m high cliff are 45° and 60° respectively.
Book – RS Aggarwal, Class 10, chapter 14, question no 22.
Hope it helps you.