Terrible diagram 1

I'm trying to figure out how long to make A and B here if I have linear actuator of length C (extended = 2C) in order to tilt my panels from completely horizontal to vertical so they avoid wind and shed snow respectively when I run up the actuator to the extremes respectively based on sensor input.

Is there a simple formula I can use to plug the length of whatever actuator I settle on to figure A and B out? I know it will have to be a certain minimum and maximum size to work properly and might have to experiment to get an idea of what works in the end, but I'd like a reasonable start point to purchase an appropriate actuator.

I've googled around and decided I'm not smart enough to even come up with the right search criteria, let alone figure this out myself since it's been 35 years since I've used anything except the most basic trig.

This isn't really homework except for the fact that I'm trying to make my home work right.

Edit: seems like if I select A=.75C and solve for B at horizontal, then it always works out. No idea why, but the couple examples I try seem to agree.