1. An observer 80 ft above the surface of the water measures an angle of depression of 0.7o to a distant ship. How many miles is the ship from the base of the lighthouse? (5280 ft = 1 mile)
Commercial airliners fly at an altitude of about 10 km. They start descending toward the airport when they are far away, so that they will not have to dive at a steep angle.

2 a) If the pilot wants the plane's path to make an angle of 3o with the ground, at what horizontal distance must the plane start descending?

b) If the pilot starts descending a ground distance of 300 km from the airport, what angle will the plane's path make with the horizontal?

3. A submarine at the surface of the ocean makes an emergency dive, making an angle of 21o with the surface. If it travels for 300 m along a downward path, how deep will it be?