Pre-Calculus. Chapter 6 Additional Topics in Trigonometry. 6.2 The Law of Cosines. Objectives: Use Law of Cosines to solve oblique triangles (SSS or SAS). Use Law of Cosines to model & solve real-life problems. Use Heron’s Area Formula to find areas of triangles.
Additional Topics in Trigonometry
x= bcosAand y = b sin A.
Hint: Find the largest angle first.