A triangle has sides A, B, and C. Sides A and B are of lengths #4# and #2#, respectively, and the angle between A and B is #(3pi)/8 #. What is the length of side C?

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Answer 1 · 2016-10-16T02:17:02

Side C is approximately #3.725#.

#c^2=a^2 +b^2 -2abcosC#

where #a, b and c# are lengths of the sides of a triangle and #C# is the measure of the angle between sides a and b.

#c^2=4^2 +2^2-2(4)(2)cos((3pi)/8)#

#c^2=16+4-16(0.3827)#

#c^2=13.877#

#c=3.725#