Lesson 2: 6.2 Law of Cosines
Duration of Days: 2.5
Lesson Objective
Use the Law of Cosines to solve oblique triangles
Use the Law of Cosines to model and solve real life problems.
Use Heron's Area formula to find areas of triangles
How do you use trigonometry to solve and find areas of oblique triangles?
Law of Cosines
HSG-SRT.D.11: Understand and apply the Law of Sines and the Law of Cosines to find unknown measurements in right and non-right triangles (e.g., surveying problems, resultant forces).
Use Khan Academy
Students will learn how to apply the Law of Cosines to solve oblique triangles, and use Heron's Area formula to find the area.
Use the Law of Cosine to find the length of the guy wires that anchor a tower.
If students are struggling with the order of operations in the law of cosines, have them use the alternate form of the law of cosines.
More advanced students can go around the building using the Law of cosines to measure distances through walls.
Use common resources
PreCalc with Limits