10.2 The Cosine Rule
The cosine rule can be used when
(i) two sides and the included angle, or
(ii) three sides of a triangle are given.
(A) If you know 2 sides and 1 angle between them [included angle] Þ Cosine rule
Calculate the length of AC
, in cm for the triangle above.
(B) If you know 3 sides ÞCosine rule
Calculate ÐBAC for the triangle above.