The velocity relative to ground is the sum of the velocities:
500mph pointing west
200mph pointing north east (from south west)
Alright, this is very confusing.
Q. Suppose an airplane is pointing due west and flying with an airspeed of 500mph, and that there is a 200mph wind out of the south west. Find the velocity vector of the plane relative to the ground. What is the speed of the plane relative to the ground?