Native Americans had an interesting and unique method of determining the height of a tree. They’d stoop down and peer down their legs! They’d travel far enough away from the tree to reach a spot where they could only view the tree’s top (from their upside down position). The distance between this location and the base of the tree was roughly equal to the tree’s height. Is it effective? Actually, it does, and the reason is rather straightforward. The angle formed by looking through the legs of a normal, fit, and healthy adult (one who can bend over in this manner) is roughly 45 degrees. The angle between the tree trunk and the ground is close to 90 degrees, therefore you can work out the tree’s height using what you know about triangle angles and sides. The tree’s height and the distance between the tree and the human are roughly equal. As a result, knowing the tree’s distance provides you a decent sense of the tree’s height.