Question 188645
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Applicable form of the Law of Cosines:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  a^2 = b^2 + c^2 - 2bc\,\cos(A)]


or, more to the point for this problem:



*[tex \LARGE \ \ \ \ \ \ \ \ \ \  a = sqrt{b^2 + c^2 - 2bc\,\cos(A)}]


Substitute your values:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  a = sqrt{(4)^2 + (7)^2 - 2(4)(7)\,\cos(50)}]


Get out your calculator and have at it.  Remember to round to the nearest hundredth.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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