The calculated distance (air line) between Houdeng-Goegnies and Ixelles is approximately 25 miles respectively 40 kilometers.
By car or train, the actual journey to Ixelles is certainly longer, as only the direct route (as the crow flies) between Houdeng-Goegnies and Ixelles has been calculated here.
Air line (approximately)
40 kilometers
22 nautical miles