# Help with the law of cosines

1. Jan 19, 2010

### finfanrb23-rw

1. The problem statement, all variables and given/known data

Two geological field teams are working in a remote area. A global positioning system (GPS) tracker at their base camp shows the location of the first team as 39 km away, 11° north of west, and the second team as 30 km away, 38° east of north. When the first team uses its GPS to check the position of the second team, what does the GPS give for the following?
(a) the second team's distance from the first team
(b) the second team's direction from the first team, measured relative to due east

2. Relevant equations

The law of cosines

c^2=a^2 + b^2 - 2ab Cos

3. The attempt at a solution

Alright I got part a) using the law of cosines and solving for c... But for the life of me I can't figure out b)! I know it's something simple I'm overlooking, considering I have all of the sides... And one angle... Any help would be greatly appreciated...

2. Jan 19, 2010

### rock.freak667

You'll need to use the sine rule

$$\frac{A}{sinA}=\frac{B}{sinB}=\frac{C}{sinC}$$