...Hello, im stuck on finding the angles in the following triangle in order to find the resultant forces.

I have this traingle;

which i want to find out all the angles for. I know that the following is;

Rx = 153.2

Ry = 128.56

Here is the angles my teacher found... somehow;

ive tried using the cosine rule, in combination with the resultant x and y forces, but it didnt work

any tips?

Thanks allot