So I have a 2D-triangle with three different values.

I've figured out that by doing cos A = ((a^2)+(b^2)-(c^2))/2*a*b that the angle of A is 69 degrees.

But now I try to figure out the other angles by using sinA/a = sinB/b = sinC/c, which means that sinB = (sinA*b)/a

However, when I try to do it I get that sin69 = 0,93. Now I can't get the sinB = (sinA*b)/a to work since that means that when I insert the values I get (0,93*8)/5,2 = 1,27

Obviously I can't get an angle by sin^-1 1,27 since it's not a value between -1 and 1. So now I'm stuck and I need some help trying to figure out where I might've gone wrong. Anyone?