As I did more research I found the follow...
"The theorem would have the distance to your arrow hitting the ground, but the reality is that your arrow is actually hitting the body of the deer well short of that point. If the deers chest is 4' off the ground, you're taking roughly 2yds of distance off that "C squared" line. So instead of total distance being 31.6yds, it's probably more like 29yds.
Thus if you are dead zero at 30yds, your arrow is actually still a bit high and dropping at the 29yd mark, and thus you hit a bit high.
If you are taking a quality shot, the variance shouldn't be anything to worry about at such distances."
I was going to give you a web site for the math but add this...So in my opinion I would get a target and set up your treestand and a 3-D target and some help and and practice...Also remember form and the basics