An aeroplane is flying horizontally at 80m in still air.if the aviator wishes to flydue South and the wind blowing the south east at 30m and the wind blowing the south east at 30m .
assuming you mean the wind is blowing from the SE, then let's say the plane is flying at an angle θ south of SE. Then if you draw the vector triangle, you can use the law of sines to get
80/sin135° = 30/sin(45°-θ) = v/sinθ
where v is the resultant speed due south
This gives the heading the pilot must fly: 150°
His actual southward speed will be 55.923 km/hr, due to the 30 km/hr headwind