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

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.

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

Cases: 1 ASA or SAA 2 SSA 3SAS 4SSS LAW OF SINES LAW OF COSINES

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

Law of Cosines:

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.

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

Law of Cosines:

Heron’s Formula: SSS

Example 7: Find the area of ∆XYZ.

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

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

math! 4-7a Assignment: TX p298, 2-24 even Assignment for Wednesday: 4-7b Assignment: TX p , even Unit 4 Test Monday 10/21