How do I find Vector C in a non-right triangle using the Law of Cosines?

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SUMMARY

The discussion centers on finding Vector C in a non-right triangle using the Law of Cosines. Given Vector A at 1.96N and 20°, and Vector B at 1.71N and 65°, the angle opposite Vector C is determined to be 95°. The Law of Cosines formula, C² = A² + B² - 2AB cos(c), is confirmed as the appropriate method to calculate the length of Vector C. The user expresses a need for a diagram to visualize the problem better.

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Homework Statement


Vector A: 1.96N at 20° Vector B: 1.71N at 65°
There are different parts I did the graph part by hand. I am having trouble finding it analytically. We have to use cm for our triangle.

Homework Equations

The Attempt at a Solution


Vector A: 1.96 cm at 20°
Vector B: 1.71 cm at 65°
Vector C: ? at 95°
180°-85°=95°
Then I had trouble after that since it isn't a right triangle. Would I use sine laws or cosine laws? I am lost.
 
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If I understand the problem correctly, side ## A ## makes an angle of 20 degrees with side ## C ##, and the angle opposite side ## C ## is angle ## c= 65 ## degrees. If that is correct, the law of cosines can be used to find side ## C ##: ## \\ ## ## C^2=A^2+B^2-2AB \cos(c) ##. ## \\ ## It would help to have a diagram, but I think I got it right.
 
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Charles Link said:
If I understand the problem correctly, side ## A ## makes an angle of 20 degrees with side ## C ##, and the angle opposite side ## C ## is angle ## c= 65 ## degrees. If that is correct, the law of cosines can be used to find side ## C ##: ## \\ ## ## C^2=A^2+B^2-2AB \cos(c) ##. ## \\ ## It would help to have a diagram, but I think I got it right.

Thank you, I wish i knew how to put up a triangle...
 
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