The calculated distance (air line) between Žďár nad Sázavou and Třinec is approximately 123 miles respectively 197 kilometers.
By car or train, the actual journey to Třinec is certainly longer, as only the direct route (as the crow flies) between Žďár nad Sázavou and Třinec has been calculated here.
Air line (approximately)
197 kilometers
106 nautical miles