Trig
posted by Isaac
A ship leaves port at 6 am and heads due east at 20 knots. At 10 am, to avoid a storm the ship changes course to N 47° E.. (47° east of north). Find the ships distance from port at 4 pm.

Reiny
first path:
4 hrs at 20 knots = 80 n miles
second path:
6 hrs at 20 knots = 120 n miles
angle between them = 90+47 = 137°
I see a clear case of the cosine law:
let x be the distance from port
x^2 = 80^2 + 120^2  2(80)(120)cos137
= ....
x = √....
you do the buttonpushing 
Isaac
Sorry what do you mean by ^ ?

lufet
186.66 miles
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