This is the basic and conceptual question from trigonometry (height and distance) in which we are to calculate the height of the tower and the width of the canal if a T.V. Tower stands vertically on a bank of a river. From a point on the other bank directly opposite the tower, the angle of elevation of the top of the tower is 60∘. From a point 20 m away this point on the same bank, the angle of elevation of the top of the tower is 30∘.
Book RS Aggarwal, Class 10, chapter 14, question no 15.