[填空题]
An airplane leaves Doha airport1q6x bv4 7gwan bouno+,eh w8ty y;)-uh mdt6 guy71kq h)tnd for Paris Charles de Gaulle airport. There are lights located at the end of th1h w)ue qtn- tyo6g8 +7uyd,h);k yhtme runway at points A(0, 4) and B(6, 8), relative to a terminal at the origin. The takeoff path of the airplane is the perpendicular bisector of line AB.
1.Find the equation of the takeoff path in the form $ax + by + d = 0$, where $a, b, d \in \mathbb{Z}$.
The airplane travels at an average speed of $570km\:hr^{-1}$ in a straight line. Once the airplane has reached cruising altitutde, an air traffic controller at the top of a 200m high air traffic control tower at C(7,0) observes that the angle of elevation to the airplane is $40^{\circ}$. Five minutes later, the controller observes that the angle of elevation is $10^{\circ}$.
2.Find the cruising altitude of the airplane in metres. m
As the airplane is about to land at the Paris Charles de Gaulle airport, the pilot is asked to delay the landing due to a traffic issue. The pilot is instructed to turn the airplane on a bearing of $045^{\circ}$ for 10km until reaching point P, then travel on a bearing of $165^{\circ}$ for 30km to point Q before flying back to the original point O for landing.
3.Find the angle OP̂Q. $^{\circ}$
4.Find the shortest distance from Q back to O for landing. km
5.Find the bearing the airplane must travel on to get back to O from Q. $^{\circ}$
