The calculated distance (air line) between Lenart v Slov. Goricah and Maribor is approximately 9 miles respectively 14 kilometers.
By car or train, the actual journey to Maribor is certainly longer, as only the direct route (as the crow flies) between Lenart v Slov. Goricah and Maribor has been calculated here.
Air line (approximately)
14 kilometers
8 nautical miles