Two ships leave a port at the same time. The first ship sails on a bearing of 39° at 18 knots (nautical miles per hour) and the second on a bearing of 129° at 12 knots. How far apart are they after 1.5 hours? (Neglect the curvature of the earth.) After 1.5 hours, the ships are approximately (Round to the nearest nautical mile as needed.) nautical miles apart.