The angle of elevation of a jet plane from a point A on the ground is 60 ° . After a flight of 20 seconds at the speed of 432 km / hour , the angle of elevation changes to 30 ° . If the jet plane is flying at a constant height, then its height is:

Step-by-step solution

tan 60 ° = h y 3 = h y ⇒ h = 3 y   … 1 tan 30 ° = h x + y 1 3 = h x + y ⇒ 3 h = x + y   … 2 Speed 432   km   h - 1 ⇒ 432 × 20 60 × 60 ⇒ 12 5   km 3 h = 12 5 + y 3 h - 12 5 = y from 1 h = 3 3 h - 12 5 h = 3   h - 12 3 5 h = 6 3 5   km h = 1200 3   m