9) a vertical tower stands on a horizontal plane and is surmounted by a vertical flag-staff of height 5 metres.at a point on the plane,the angles of elevation of the bottom and the top of the flag-staff are respectively 30 degree and 60 degree.find the height of the tower.
Let h be the height of the tower.
In right ΔDBC,
In right ΔABC,
Thus, height of the tower = 2.5 m