1. I don't know which trigonometry you use to do this problem. Therefore I'll use vectors to show you how to solve it.

2. Define a coordinate system with the origin at the center of the Earth, the x-axis pointing to E(E90°; N0°) and the y-axis pointing N(E180°; N0°), the z-axis pointing to the Northpole. Then every place on the surface of the Earth is determined by unit stationary vector.

3. The town Qingdao (E120°; N36°) is determined by:

with

4. The point F is determined by

5. The angle which is included by and is calculated by:

You'll get

6. Since 1° represents a distance of 60 nautical miles (nmi) you'll get:

At a speed of the elapsed time will be 220 h.

7. Be sure that you pass the south Korean islands and the south japanese islands at a safe distance