Law of Sine and Law of Cosine Review

Three boats are out at sea: Boat A, Boat B, and Boat C. The crew of Boat A can see both Boat B and Boat C. The angle between the line of sight to Boat B and the line of sight to Boat C is 49°. If the distance between Boat A and Boat B is 1.8 miles and the distance between boat A and Boat C is 3.2 miles, what is the distance between Boat B and Boat C?

• 2.4 miles

• 5.3 miles

• 1.3 miles

• 3.7 miles

Find the area to the nearest tenth

Find AB

• 10

• 8

• 6.1

• 4.9

Which of the following formulas shows the Law of Cosines?

• c² = a² + b² - 4ac + cosA

• c² = a² - b² - 2abcosC

• c² = a² + b² - 2abcosC

• (cos A)/a = (cos B)/b

Which law would you use?

• Law of Sines

• Law of Cosines

Find m<A to the nearest whole degree.

Would you use the Law of Sines

or the Law of Cosines?

• Law of Sines

• Law of Cosines

Choose which law you need to solve the problem (DO NOT SOLVE):

• Law of Sines

• Law of Cosines

• Both

• Neither

Solve the Triangle(s): A = 26^o, a = 5, b = 9

• no triangle possible

• B = 14^o, C = 21^o, c = 8.7

• B = 52^o, C = 102^o, c = 11.2

• B = 52^o , C = 102^o, c = 11.2

  OR

  B = 128^o, C = 26^o, c = 5.0

Which law would you use?

• Law of Sines

• Law of Cosines