+47 Ok so I've posted this question for a day now and no one answered yet so if you can please do so:https://web2.0calc.com/questions/geo-folding-problem
I really appreciate it because I have answered my fair share of questions and I usually only ask one or two per week 
+36916 See image below : (check my numbers+)
The diagonal forms a 36 . 0273 angle folding it over produces a further reduction of 36.0273 of the 90 degree angle in the corner
resulting in an angle of the single paper of 17.9453 degrees
you have ONE side of the triangle already : 8
now you can use the tan funtion to find x then the are of the single thickness (one of them) is 1/2 8 * x
