The calculated distance (air line) between Le Mont-sur-Lausanne and Rapperswil is approximately 113 miles respectively 182 kilometers.
By car or train, the actual journey to Rapperswil is certainly longer, as only the direct route (as the crow flies) between Le Mont-sur-Lausanne and Rapperswil has been calculated here.
Air line (approximately)
182 kilometers
98 nautical miles