1. Law of Cosines & Heron’s Formula Objective: Be able to use Law of Cosines & Heron’s formula to solve oblique triangles as well as find their area. TS: Explicity assess information and draw conclusions Warm-Up: Recall the Law of Cosines and use it to find c, in the triangle with C=107°, a=10 and b=12.

2. Solve the triangle where a=17.1, b=10.3 and c=21.7

3. Heron’s Area Formula

4. Solve for θ & y given the below figure is a parallelogram. Then find the area θ 120° y 35 25

5. Solve for θ & y given the below figure is a parallelogram. Then find the area θ 120° y 35 25

6. θ 120° y 35 25 Solve for θ & y given the below figure is a parallelogram. Then find the area

7. Determine if Law of Sines or Cosines would be needed to start solving the triangle a)A = 15°, B = 58°, c = 94 b)a = 96, b = 43, A = 105° c)a = 24, b = 16, c = 29 d)a = 15, c = 42, B = 49°

8. 1)Solve the triangle a = 31, b = 52, c = 28 2)Find the area of the triangle with sides, 31, 52 and 28 inches in length. Answers: A = 29.797°, B = 123.533° & C = 26.670° Area = 361.768 in 2