16. The angles of elevation of the top of a tower from two points at a distance of 4 m and 9 m from the base of the tower and in the same straight line with it are complementary. Prove that the height of the tower is 6 m.
Let the height of the tower be m.
we have PB = 4m and QB = 9 m
Suppose , so
According to question,
In triangle ,
..............(i)
In triangle ,
.....................(ii)
multiply the equation (i) and (ii), we get
Hence the height of the tower is 6 m.