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2.  This Week at a Glance  Return Ch. 13 Quizzes  13.5A Notes  Assignment: 13.5 Skills Practice

3.  Monday: 13.5A Law of Cosines  Tuesday: 13.5B Law of Cosines  Wednesday: Ch. 13A Review  Thursday: Ch. 13A Test  Friday: Begin Ch. 13B ~ Unit Circle

4. 2) Write an equation involving sine, cosine, or tangent that can be used to find x. Then solve the equation, rounding to the nearest degree.

5. Solve 3) Solve ∆ABC if m  A = 20 , m  C = 90 , and b = 10. Round measures of sides to the nearest tenth and measures of angles to the nearest degree.

6. 4) Using the Law of Sines, find the measure of angle A when c = 15, m  B = 50 , and b = 12.4. A B C

7.  solve problems by using Law of Cosines.

8. Example 1-4a TermDefinitionExample Law of Cosines In any  ABC, Use Law of Sines when given _______, or _______. SAS SSS c A C a B b a 2 = b 2 + c 2 – 2bc  cos A b 2 = a 2 + c 2 – 2ac  cos B c 2 = a 2 + b 2 – 2ab  cos C

9. In  ABC, find c.

10. In  ABC, find r. r

11. A ranger tower at point A is directly north of a ranger tower at point B. A fire at point C is observed from both towers. The distance from the fire to tower A is 60 miles, and the distance from the fire to tower B is 50 miles. If m  ACB = 62 , find the difference between the towers. A B C 50 62 60 c

12. 13.5 Skills Practice #1 – 6