An offshore lighthouse is 2 km from a Coast Guard station A and 3 km from a hospital B near the shoreline.

Question

If the angle formed by light beans to A and B is 150, what is the distance line AB between the coast guard station and the hospital?

Answer 1

This is a direct application of the law of cosines.

The square of the distance AB is 9 + 4 -12 cos 150°.