Law of Cosines

  1.   \rhd Solving for a side of the triangle with the law of cosines. (4:38)
    Side b of a triangle is 12 and side c of a triangle is 9, and the angle contained between them is 87 degrees.  What is the length of the other side of the triangle? Solution: a \approx 14.62
  2.   \rhd Solving for an angle with the law of cosines. (6:41)
    Given a triangle with base 60 m and other sides 50 m and 20 m, find the angle \theta between the base and the longer side of the triangle. Solution: \theta \approx 18.19 degrees.
  3.   \star Solve a triangle using the law of cosine
  4.   \rhd Proof of the law of cosines (9:26)