A ferryboat transports tourists among three islands. It sails from the first island to the second island, 5.98 km away, in a direction 37.0° north of east. It then sails from the second island to the third island in a direction 78.0° west of north. Finally, it returns to the first island, sailing in a direction 28.0° east of south.
(a) Calculate the distance between the second and third islands.
(b) Calculate the distance between the first and third islands.