Books are like mirrors: if a fool looks in, you cannot expect a genius to look out - J.K. Rowling
A window washer is working in a hotel building. An observer at a distance of 20m from the building finds the angle of elevation of the worker to be of 30°. The worker climbs up 12 m and the observer moves 4m farther away from the building. Find the new angle of elevation of the worker?