Unit A: Geometry

Chapter 3: Trignometry

Summary

Choosing the Cosine Law or the Sine Law

• To find missing information in a triangle, three or more known values must be given.

• If a triangle has a matching pair and one other given value, the sine law is used.
  
  
• When presented with a triangle, use the cosine law if
• three side lengths are given
• two side lengths and the angle in between are given

• In all other cases, use the sine law.

• If a combination of four angles and sides are given, there will always be a matching pair.