A sail boat on lake Huron leaves Southampton and sails 20 degrees west of north for 20km. At the same time, a fishing boat leaves Southampton and sails 30degrees west of south for 15 km. At this point, hot far apart are the boats, to the nearest kilometer?

Answer 1

After making your sketch, you will see that the angle between their paths
is 130°, so the cosine law would be a good idea

if d km is the distance between them, then
d^2 = 20^2 + 15^2 - 2(20)(15)cos 130°

take it from here.

Answer 2

On a nautical note, if you sail 15 km at 30° west of south from Southhampton, you boat would be grounded near Port Elgin.