Draw a picture to help. In triangle ABC, A is the plane, B a point in the air at the same height as the plane and directly over the tower, and C is the base of the tower. Point D is on the line BD and represents the top of the tower. AB=1050m; CD is the height of the tower; angle BAC=41 deg; BAD=36 deg. BC=1050tan41; BD=1050tan36 so CD=BC-BD=1050(tan41-tan36)=149.88 or 150m to the nearest metre. The shortest distance, AC, is given by AB/AC=cos41, so AC=1050/cos41=1391m to the nearest metre.