1. Law of Cosines

2. SAS Area Formula: A b c Heron’s SSS Area Formula: b c a

3. Example 1Area of a Triangle --- SAS a) 48º 14 b) 85º 12 23

4. Example 2Area of a Triangle --- SSS a) 14 13 18 b) 10 20 18

5. Law of Cosines A c b Use When Given: SSS or SAS a

6. Example 4Law of Cosines [A] 15 100° 12 x [B] 30 x°x° 10 21 Remember inverse of trig function to solve for angles!

7. Law of Sines AB C a c b Use When Given: AAS, ASA, or SsA

8. Example 3Law of Sines [A] x 28°40° 20 [B] x 38°60° 10

9. Example 5Applications [A] Two rangers are 12 miles apart on a service road, both sight a fire north of the road. Ranger A has a line of sight 38° with the road, and Ranger B has 63° line of sight. How far is each Ranger from the fire? A B 63º38º x y 12 miles 79º