Question 1107840
Two boats left the harbour at the same time.
 One travelled at 10km/h on a bearing pf N47'E.
 The other travelled at 8km/h on a bearing of N79'E.
 How far apart were the boats after 45 min?
 Round your answer to the nearest tenth of a kilometre.
:
the angle between the paths of the two boats: 79 - 47 = 32 degrees
find how far each boat has traveled in 45 min ({{{3/4}}} hr)
Boat l:{{{3/4}}} * 10 = 7.5 km 
Boat 2: {{{3/4}}} * 8 = 6 km
Use the law of cosines a^2  = b^2 + c^2 - 2(b*c)*cos(A) where
a = distance between the boats after 45 min
b = 7.5 km
c = 6 km
A = 32 degrees
a^2 = 7.5^2 + 6^2 - 2(7.5*6)*cos(32)
a^2 = 56.25 + 36 - 2(45)*.848
Do the math, I got:
a = {{{sqrt(15.92567)}}}
a = 4.0 km