Answer:
1027 miles
Step-by-step explanation:
Using the Law of Cosines, the distance "c" between the mountains can be found from ...
c^2 = a^2 + b^2 -2ab·cos(C)
= 3964^2 +3960^2 -2·3964·3960·cos(14.9°)
≈ 1,055,634.95
So, the distance is about
c ≈ √1055634.95 ≈ 1027.44
The straight-line distance (partially through the Earth) from one mountaintop to the other is about 1027 miles.