The calculated distance (air line) between Saint-Arnoult-en-Yvelines and Le Mans is approximately 89 miles respectively 143 kilometers.
By car or train, the actual journey to Le Mans is certainly longer, as only the direct route (as the crow flies) between Saint-Arnoult-en-Yvelines and Le Mans has been calculated here.
Air line (approximately)
143 kilometers
77 nautical miles