The calculated distance (air line) between Bochum-Hordel and Porz am Rhein is approximately 43 miles respectively 69 kilometers.
By car or train, the actual journey to Porz am Rhein is certainly longer, as only the direct route (as the crow flies) between Bochum-Hordel and Porz am Rhein has been calculated here.
Air line (approximately)
69 kilometers
37 nautical miles