Chapter 10 Solution of Triangles

1. Sin rule :

a/sin A = b/sin B = c/sin C

2. An ambiguous case will arise if given the two sides a and b , where a is shorter than b, and the acute angle A is not the included angle.

3. Cosine rule :

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

4. Area of triangle ABC

= 1/2 ab sin C

= 1/2 ac sin B

= 1/2 bc sin A