Question 1120726
{{{b^2+c^2-2bc*cos(120)=a^2}}}


{{{a^2=(42.3)^2+(136.4)^2-2(42.3)(136.4)*cos(120)}}}


{{{a^2=(42.3)^2+(136.4)^2-2(42.3)(136.4)*(-1/2)}}}


{{{a^2=(42.3)^2+(136.4)^2+(42.3)(136.4)}}}


{{{a=161.752805}}}--------length of side opposite point A.


Now use Law Of Sines to find measure of angle at point B.