1. 5.6
Law of Cosines

2. What you’ll learn about
Deriving the Law of Cosines
Solving Triangles (SAS, SSS)
Triangle Area and Heron’s Formula
Applications
… and why
The Law of Cosines is an important extension of the
Pythagorean theorem, with many applications.

3. Law of Cosines

4. Example Solving a Triangle (SAS)

5. Example Solving a Triangle (SAS)

6. Example Solving a Triangle (SAS)

7. Area of a Triangle

8. Heron’s Formula

9. Example Using Heron’s Formula
Find the area of a triangle with sides 10, 12, 14.

10. Example Using Heron’s Formula
Find the area of a triangle with sides 10, 12, 14.