The calculated distance (air line) between Rheda-Wiedenbrück and Bochum is approximately 53 miles respectively 85 kilometers.
By car or train, the actual journey to Bochum is certainly longer, as only the direct route (as the crow flies) between Rheda-Wiedenbrück and Bochum has been calculated here.
Air line (approximately)
85 kilometers
46 nautical miles