The breadth of a street between two houses is 30 meters and the angle of the depression of the top of one, as observed from the top of the other which is 40 meters height is 30°. Find the height of the other house. From a light house the angle of depression of two ships on opposite sides of the lighthouse be 100 m. Find the distance between the ships the line joining them passes through the foot of the light house. An aeroplane when 2000 meters high passes vertically above another at an instant when the angle sof elevation at the same observing point are 63° and 45° respectively. How many meters in the one lower than the other.