Answer:
46 meters
Step-by-step explanation:
In the figure you can see law of cosines.
In your case
α = 22.5° + 42 ° = 64.5 °
b = 15 m (distance between your's tent and Joe's tent)
c = 42 m (distance between your's tent and Karl's tent)
a is the distance between Joe's tent and Karl's tent
Replacing in the first equation:


