Exercise 4.5.5
Let \(a\) represent the height of the building and \(h\) the height of the antenna. Then the following relationships hold:
\(a=50\tan40^\circ\approx42\) ft, \(a+h=50\tan52^\circ\). Therefore, \(50\tan40^\circ+h=50\tan52^\circ\). So \(h=50(\tan52^\circ-\tan40^\circ)\approx22\) ft.