Some Applications of Trigonometry

If the angle of elevation of the sun is 30° and the height of a tower is 10 m, then the length of the shadow is:

The angle of elevation of a jet fighter from a point A on the ground is 60°. After a flight of 15 seconds, the angle of elevation changes to 30°. If the jet is flying at a constant height of 1500√3 m, the speed of the jet in km/h is:

The top of a 20 m high tower makes an angle of elevation of 45° from the bottom of an electric pole and angle of 30° from the top of the pole. The height of the electric pole is:

A person standing at the bank of a river observes that the angle of elevation of the top of a tree on the opposite bank is 60°. When he retreats 20 m from the bank, the angle becomes 30°. The height of the tree and width of the river are:

The angles of elevation of the top of a tower from two points at a distance of \(4\text{ m}\) and \(9\text{ m}\) from the base of the tower and in the same straight line with it are complementary. Find the height of the tower.