I know you have to use cos law, but I first found the chord of the window and then found the angle. Then used cos law and used two of the missing numbers as one and solved it out for the variable, but no success

This is another similar question I dont get:

The height of a gothic window is 4.72 m and the radii of the arcs forming the arch are 8.94 m. Determine the width of the arch.