Computer · Surveying

A theodolite is placed at P and a 5 m long vertical staff is held at Q. The angle of depression made when reading the 3.5 m mark on the staff is 7°15'. The horizontal distance between P and Q is 2500 m. The height of the instrument at P is 1.5 m and the reduced level (RL) of point P is 980.450 m. Taking curvature and refraction corrections into account, determine the RL of point Q (in m).