Answer:
[tex]x=117.9^o[/tex]
Step-by-step explanation:
Since you are given the three sides, use the law of cosines, that is:
[tex]2\,(50)\,(55) \,cos (x)=50^2+55^2-90^2\\cos(x)=\frac{-2575}{5500} =-\frac{117}{250} \\x=arccos(-\frac{117}{250})\\x=117.9^o[/tex]
