Answer:
The circumference of the wheel is 2 * pi * r = 2 * 3.14 * 225 mm = 1413.8 mm.
The number of arcs between each spoke is 25 - 1 = 24.
So, the arc length between each spoke is the circumference of the wheel divided by the number of arcs, which is 1413.8 mm / 24 = 58.91 mm.