trig
posted by Danielle .
a lighthouse is located at point A. a ship travels from point B to point C. At point B,, the distance between the ship and the lighthouse is 7.5km. At point C the distance between the ship and the lighthouse is 8.6km. Angle BAC is 58 degrees. Determine the distance between B and C.

This is just a straightforward law of cosines problem. We want to find a, given A,b,c.
A=58°, c=7.5, b=8.6
a^2 = b^2+c^2  2bc cosA
plug and chug. . .