Warm-Up 10/15

1. Warm-Up 10/15 1. H PSAT Tomorrow 10/16, you will need to bring your own calculator.

3. Rigor:You will learn how to use the Law of Sines and Cosines to solve right triangle problems.Relevance:You will be able to use the Law of Sines and Cosines to solve real world problems.

4. 4-7b Law of Sines and the Law of Cosines

5. Cases: • ASA or SAA 2 SSA 3 SAS 4 SSS LAW OF SINES LAW OF COSINES

6. Example 4: Find two triangles for which A= 43°, a= 25, b= 28. Round side lengths to the nearest tenth and angle measures to the nearest degree. A is acute, and h = 28sin 43° 19.1 Since a < b and a > h there are two different triangles. Solution 1: Find the acute  B. , C , and c 36.6

7. Example 4: Find two triangles for which A= 43°, a= 25, b= 28. Round side lengths to the nearest tenth and angle measures to the nearest degree. Solution 2: Find the obtuse  B'. CB'B =  B , so  B' 180°– 50° 130°  C 180°– 43 °– 130° 7° , C , and c 4.5

8. Law of Cosines:

9. Example 5: Solve ∆ABC. Round side lengths to the nearest tenth and angle measures to the nearest degree. Given a = 6, b =24, c = 20 find angle A.

10. Example 6: Solve ∆ABC. Round side lengths to the nearest tenth and angle measures to the nearest degree. , , and c

11. Law of Cosines:

12. Heron’s Formula: SSS

13. Example 7: Find the area of ∆XYZ.

15. Example 8: Find the area of ∆GHJ to the nearest tenth.

16. math! • 4-7a Assignment: TX p298, 2-24 even • Unit 4 Test • Monday 10/21

17. math! • 4-7a Assignment: TX p298, 2-24 even • Assignment for Wednesday: • 4-7b Assignment: TX p298-299, 26-50 even • Unit 4 Test • Monday 10/21