It's puzzle time again!

[N. W. Perry]

I let GeoGebra do the job and it tells me that the 0 point for 8 - ((26-36 tan (A))/cos(A)) is 27,7222764 degrees

Making BC = 18,91828 LDU

What did you enter into GeoGebra to find this? I sketched it there myself, but I don't know how to enter all of the constraints I need. (Dimensions are different in my sketch because I was dealing with different parts, but the problem is the same.)