Solve the following question:
Question: The flying height for a vertical photograph above the downtown area of a city is 1980 meters. The focal length of the camera lens is 209.55 mm. The distance measured from the center of the photograph to the image of the bottom of a radio tower is 71.73 mm, and the distance to the image of the top of the tower is 79.86 mm.
Question 1: Compute the tower height.
Express your knowledge to solve the above question. Thanks.