The calculated distance (air line) between Beni Mellal and Sidi Slimane is approximately 135 miles respectively 218 kilometers.
By car or train, the actual journey to Sidi Slimane is certainly longer, as only the direct route (as the crow flies) between Beni Mellal and Sidi Slimane has been calculated here.
Air line (approximately)
218 kilometers
118 nautical miles