<PRE><B>Question 979889</B>

Given vectors of magnitude 3 and 4 with an angle between them of 80°, find the magnitude of the resultant. 
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Place the start of one vector at the end of the first.
The resultant is the 3rd side of the triangle.
The interior angle = 100 degs
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Use the Cosine Law:
r^2 = 3^2 + 4^2 - 2*3*4*cos(100)
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