The calculated distance (air line) between Mymensingh and Nārāyanganj is approximately 79 miles respectively 127 kilometers.
By car or train, the actual journey to Nārāyanganj is certainly longer, as only the direct route (as the crow flies) between Mymensingh and Nārāyanganj has been calculated here.
Air line (approximately)
127 kilometers
69 nautical miles