Concepts and Examples on Cosine Rule

0:00 Introduction
0:36 Why do we learn the Cosine Rule
4:01 Derivation of the Cosine Rule for an acute angled triangle
9:13 Derivation of the Cosine Rule for an obtuse angled triangle
13:03 The Cosine Rule
15:21 Practice Now 9
22:05 Practice Now 10
26:15 Let's Try !