Happy π Day! It’s also Einstein’s birthday. π, a transcendental number, is the ratio of a circle’s circumference to its diameter. It has been calculated to over a trillion digits after the decimal. Babylonian mathematics had a crude approximation. Two millennia ago, Chinese mathematicians had a fairly accurate approximation to seven digits. At about the same time, India was using one to five digits.
Circles are a lot of fun. Using only a compass and straight edge (no need for measuring; the compass holds the radius of the circle), you can draw all the other shapes–triangle, square, pentagon, hexagon, septagon, etc. My favorites are multiples of threes, ie, triangle, hexagon and nonagon, which can all be drawn by a special, secret method. If you connect the centers of circles drawn such that the center of the next circle is placed on the circumference of the previous circle, and then use the first two circles’ center points to define a line… Hmmm… I’d have to show you. I would guess Anaxagoras played with this while he was stuck in prison. He was the first Greek to come up with an good approximation of π during his tenure there.
Mathematics has always fascinated me, especially the very basic roots of geometry. Give a child a pad of plain paper, a (fairly good) compass and a straight edge (not a ruler). Show her a couple of ideas, then let her go with it. You might be amazed at what she can discover on her own.
Here is π to 607 digits. I stopped here because I thought it was interesting that it could have three zeros in a row, then pick up again with a 5.
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