Pythagorean [sp] therom, A squared + B squared = c squared. Carpenters use this alot [was one once] aka 3,4,5, or 6,8,10. Here's my tests and results. I have three ladder stands 12' tall, baits for bear at an average of 17 yards from base of tree stands are in, ranges 20 yds w/ rf. Standing up for the shot, I figure my bow is about 17' above ground. Using my 20 yd xhair on a block target,I got dead bear as soon as i can find one dumber than me. Much ado about nothing until you get way high up and start shooting either down hill or up hill. It's the seven "P's" guys, proper prior planning prevents pizz poor performance.