Warm Up – 2/27 - Thursday Find the area of each triangle.

Formulas sin 𝜃 = 𝑜𝑝𝑝 ℎ𝑦𝑝 cos 𝜃 = 𝑎𝑑𝑗 ℎ𝑦𝑝 tan 𝜃 = 𝑜𝑝𝑝 𝑎𝑑𝑗 𝐴𝑟𝑒𝑎= 1 2 ∙𝑏∙ℎ or 𝐴𝑟𝑒𝑎= 1 2 ∙𝑎∙𝑏∙ sin 𝜃 Law of sines: sin 𝐴 𝑎 = sin (𝐵) 𝑏 = sin 𝐶 𝑐 Law of cosines: 𝑐 2 = 𝑎 2 + 𝑏 2 −2𝑎𝑏∙𝑐𝑜𝑠 (𝐶)

Law of Sines and Cosines We use the law of cosines when we have two sides and the included angle OR three sides and an unknown angle. Generally speaking, the Law of Sines is a little bit easier to work out, so if we can just use the Law of Sines to solve a problem we do.

Practice Story Problem

Law of Sines and Cosines Practice