This means it turns some angle that it tells us leads back to the airport. Since we are northeast of the airport, any angle 0-180 degrees to the east would be moving away from the airport in an eastern direction. So the angle is going to be less than 180 degrees to the left because the plane takes this path back to the airport which is southwest of 624 km east, 326 km north.

The picture for this is a triangle. A base leg 624 km (east), another leg or the height 326 km (north) and a hypotenuse 846 km (west-southwest). To solve you can use your inverse sine

We're looking for angle X at the top of the triangle so