The starships of the Solar Federation are marked with the symbol of the federation, a circle, while starships of the Denebian Empire are marked with the empire's symbol, an ellipse whose major axis is
1.40 times longer than its minor axis ($a$ = 1.40$b$ in $\textbf{Fig. P37.45}$). How fast, relative to an observer, does an empire ship have to travel for its marking to be confused with the marking of a federation ship?