The calculated distance (air line) between Ōita and Bungo-Takada-shi is approximately 24 miles respectively 39 kilometers.
By car or train, the actual journey to Bungo-Takada-shi is certainly longer, as only the direct route (as the crow flies) between Ōita and Bungo-Takada-shi has been calculated here.
Air line (approximately)
39 kilometers
21 nautical miles