Question

To find the length ab of a small lake, a surrounding veyor measured angle acb to 96, ac to be 91 yards, and bc to be 71 yards. what is the approximate length of the lake?

Answer 1

Using the law of Cosins that states: For any triangle, a, b and c are sides and C is the angle opposite side c
c² = a² + b² − 2ab cos(C)

Applying this in our problem, we get:
AB²= 71²+91²- 2x91x71 cos96
AB²=14627.7 yard²
AB=121 yard