The calculated distance (air line) between Sŭngjibaegam and Kyŏngsŏng is approximately 48 miles respectively 77 kilometers.
By car or train, the actual journey to Kyŏngsŏng is certainly longer, as only the direct route (as the crow flies) between Sŭngjibaegam and Kyŏngsŏng has been calculated here.
Air line (approximately)
77 kilometers
42 nautical miles