Find point A to point B

Question

Points A and B are separated by a lake. To find the distance between them, a surveyor locates a point C on land such than . Find the distance across the lake from A to B

Numbers on diagram provided: 543 ft, 42.8 degrees, 304 ft

Answer 1

I presume side AC is 543 feet long, and that side BC is 304 feet long (although it could be the reverse without changing the answer). Side AB is 380.83 feet, approximately.

Use the law of cosines:

c² = a² + b² – 2ab cos C

where c = AB, a = AC, and b = BC.