Question #85311
1 Answer
Resultant
Explanation:
We use the technique called the cosine rule(or the rule of cosines)
Imagine, that the parrallelogram on the far right of the picture were divided into 2 equal triangles.
Now say, the sides were labelled
Then the cosine rule could be stated as:
In our case, we can apply the rule thus:
Applying the rule: