think this has been covered
It hardly does at all. Just for the heck of it, if you're target is 50 yards away and you're 45 foot up the tree, your shot is now 52.2 yards. It takes a lot of height for it to matter.
You figure it simply by the Pythagorean theorem everyone learned in 9th grade geometry- base squared + height squared = hypotenuse squared.
Yes, work is slow this morning