In a week, arrive from long triangle bead trigonometry, go to Beijing again, many China's famous entrepreneur expresses to assentation to Ma Yun's appeal.
Calm down, Don. Dragonflies don't know trigonometry, but the research shows that their brains are organized to perform the needed computations. Your brain is too.
The Indian astronomer Aryabhata, who lived between 476 and 550 CE, developed trigonometry, recognized that the earth moved and accurately calculated both lunar and solar eclipses.
If you know the distance between your eyes — we'll call this the baseline — then you can apply some trigonometry and figure out how far away the object is.