two boats have a port at the same time. the first travels at 15km/h on a bearing 135° while the second travels at 20km/h on a bearing of 063°. if after 2hrs, the second boat is directly north of the first boat, calculate their distance apart

Answer 1

for each boat, distance = speed * time
Now draw a diagram, and note the angle θ between the two headings.
Finally, use the law of cosines:
c^2 = a^2 + b^2 - 2ab cosθ