Help needed please and thank you

The answer is about 33.7 degrees. I used trigonometry to solve this. You can use sin, cos, or tan but I decided to use sin. Sin is known to be opposite over hypotenuse. The opposite value is 50 while the hypotenuse is 90. The equation I started out with is sinФ = (50/90). In order to find the angle you have to rearrange this equation to be c = sin^-1 (50/90). I then plugged this in the calculator (be sure the mode is on degrees!) to get the answer. Hope this helped :))
using the Cosine Rule:-
50^2 = 90^2 + 55^2 - 2.90.55 cos C
cos C = (50^2 - 90^2 - 55^2) / -2*90*55)
= 0.8712
C = 29.4 degrees answer