well, 22 1/2 is the angle use for bay windows. You know what that looks like. I am not sure I am with you on your question, but this will surely assist you. the two angles added together is the total of the angle. two each of 45 degree sides makes one 90 degree corner.
As with all corners either inside or outside corners, make the corners pairs with only one foot boards then joing the angles with straight stock.