A vertical tower 15 m high stands on level ground. From point A, which is 15 m from the foot of the tower, the top of the tower is observed. Point B is on the same straight line with A and the foot, 40 m from the foot of the tower.
a. (i) Calculate, in degrees, the angle of elevation of the top of the tower as seen from point A.
b. (ii) Calculate, correct to one decimal place, the angle of elevation of the top of the tower as seen from point B.