Is there a way to create a reference plane where the angle between planes is a global variable? I wish to to have two planes be at a specific angle, but I need that angle to be a variable so that I can use a global variable equation to define some other dimensions based on that angle which may need to be adjusted. Is this possible? If not, what is another way I could do it?

I've attached a jpg screen capture so you can see what I am talking about...