Its been a while since I really had to deal with an equation like this, and I might just be missing a simple trig identity. I would really appreciate any help you might be able to give me.

I don't believe I have made any mistakes getting here because I can extrapolate the solution from a graphing calc, and the solution works in my application.

I am trying to solve for Θ in the following equation (I am working in degrees):

ΔL = (π * r * Θ / 45) - (4 * r * sinΘ)