A triangle has sides A, B, and C. Sides A and B are of lengths #9# and #9#, respectively, and the angle between A and B is #(5pi)/12 #. What is the length of side C?

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Answer 1 · 2016-04-05T16:19:46

#c=10,96" unit"#

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#c^2=a^2+b^2-2*a*b*cos((5pi)/12)#

#cos((5pi)/12)=0,259#
#c^2=9^2+9^2-2*9*9*0,259#

#c^2=81+81-2*81*0,259#

#c^2=162-41,958#

#c^2=120,042#

#c=sqrt(120,042)#

#c=10,96" unit"#