1 00:00:01,920 --> 00:00:07,080 Speaker 1: Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff, 2 00:00:07,120 --> 00:00:10,920 Speaker 1: Lauren bog Obam here. The number referred to as PIE 3 00:00:11,039 --> 00:00:15,040 Speaker 1: has mesmerized mathematicians for four thousand years. It's the rarest 4 00:00:15,080 --> 00:00:19,440 Speaker 1: of mathematical constants and unfailingly accurate ratio that's also never ending. 5 00:00:19,920 --> 00:00:22,160 Speaker 1: The digits of pie have been calculated out more than 6 00:00:22,160 --> 00:00:26,119 Speaker 1: twenty two trillion decimal places without ever repeating. That makes 7 00:00:26,160 --> 00:00:30,560 Speaker 1: it an irrational number. The definition of pie is simple. 8 00:00:30,880 --> 00:00:33,600 Speaker 1: It's the ratio of a circle's circumference, that is, the 9 00:00:33,720 --> 00:00:37,199 Speaker 1: length around the circle divided by its diameter, or the 10 00:00:37,280 --> 00:00:40,519 Speaker 1: length across the circle. But what's remarkable is that, no 11 00:00:40,600 --> 00:00:43,479 Speaker 1: matter the size of the circle you're measuring, that ratio 12 00:00:43,600 --> 00:00:47,080 Speaker 1: of circumference to diameter will always equal three point one 13 00:00:47,159 --> 00:00:50,800 Speaker 1: four one five nine, two six, five, three, five, eight, nine, seven, 14 00:00:51,120 --> 00:00:55,600 Speaker 1: et cetera, usually shortened to three point one four. Divide 15 00:00:55,640 --> 00:00:58,160 Speaker 1: the circumference of a tennis ball by its diameter and 16 00:00:58,200 --> 00:01:00,800 Speaker 1: you get three point one four. By the circumference of 17 00:01:00,840 --> 00:01:03,280 Speaker 1: the planet Mars by its diameter, and you get three 18 00:01:03,280 --> 00:01:06,080 Speaker 1: point one four. Divide the circumference of the known universe 19 00:01:06,120 --> 00:01:10,240 Speaker 1: by its diameter. You get the point Pie is critical 20 00:01:10,319 --> 00:01:14,720 Speaker 1: to several basic calculations in geometry, physics, and engineering, including 21 00:01:14,760 --> 00:01:16,840 Speaker 1: the area of a circle, which is pie times the 22 00:01:16,840 --> 00:01:19,440 Speaker 1: square of the radius, and the volume of a cylinder, 23 00:01:19,640 --> 00:01:22,679 Speaker 1: which is pie are squared times the height of the cylinder. 24 00:01:23,800 --> 00:01:27,000 Speaker 1: When the ancient Babylonians attempted to measure the precise area 25 00:01:27,040 --> 00:01:30,240 Speaker 1: of circles back in nine b c E, they assigned 26 00:01:30,280 --> 00:01:32,600 Speaker 1: a value to pie a three point one to five. 27 00:01:33,200 --> 00:01:36,119 Speaker 1: The ancient Egyptians came up with three point one six 28 00:01:36,280 --> 00:01:40,160 Speaker 1: zero five. The Greek mathematician Archimedes, working in the third 29 00:01:40,160 --> 00:01:44,200 Speaker 1: century BC, and the Chinese mathematician Zoo Changza, working in 30 00:01:44,240 --> 00:01:47,640 Speaker 1: the fifth century c E, are co credited with calculating 31 00:01:47,760 --> 00:01:52,400 Speaker 1: the most accurate approximations of pie, before calculus and supercomputers 32 00:01:52,440 --> 00:01:57,120 Speaker 1: gave us a more definitive answer. Then, in seventeen o six, 33 00:01:57,360 --> 00:02:00,880 Speaker 1: the self taught Welsh mathematician William Jones assigned the Greek 34 00:02:00,960 --> 00:02:04,640 Speaker 1: letter P to this magical number without end, possibly because 35 00:02:04,720 --> 00:02:06,480 Speaker 1: P is the first letter of the Greek words for 36 00:02:06,600 --> 00:02:11,000 Speaker 1: periphery and perimeter. The symbol's use was later popularized by 37 00:02:11,040 --> 00:02:15,400 Speaker 1: eighteenth century Swiss mathematician Leonard Euler, but wasn't adopted worldwide 38 00:02:15,480 --> 00:02:19,080 Speaker 1: until nineteen thirty four. The fact that pie can be 39 00:02:19,120 --> 00:02:22,639 Speaker 1: found everywhere, not only in circles, but in arcs, pendulums, 40 00:02:22,639 --> 00:02:26,919 Speaker 1: and interplanetary navigation, and that it's infinitely long has inspired 41 00:02:26,960 --> 00:02:29,960 Speaker 1: a cult following that includes plenty of geeky tattoos and 42 00:02:30,000 --> 00:02:33,680 Speaker 1: even its own national holiday. National Pie Day was officially 43 00:02:33,680 --> 00:02:36,440 Speaker 1: recognized by the United States Congress in two thousand nine, 44 00:02:36,800 --> 00:02:39,600 Speaker 1: but the definitely not square roots of the holiday can 45 00:02:39,639 --> 00:02:42,919 Speaker 1: be traced back to eight and a man named Larry 46 00:02:43,000 --> 00:02:47,160 Speaker 1: the Prince of Pie Shaw. Shaw was a beloved longtime 47 00:02:47,160 --> 00:02:51,160 Speaker 1: employee at the Exploratorium, a science museum in San Francisco, California, 48 00:02:51,520 --> 00:02:53,520 Speaker 1: and came up with the idea of Pie Day on 49 00:02:53,560 --> 00:02:55,880 Speaker 1: a nineteen eighty eight staff retreat following the death of 50 00:02:55,880 --> 00:03:01,000 Speaker 1: Exploratory and founder Frank Oppenheimer. The date for celebration and well, 51 00:03:01,080 --> 00:03:03,400 Speaker 1: because the first digits of pie are three point one 52 00:03:03,440 --> 00:03:08,959 Speaker 1: four March fourteen, or three fourteen. Even better, March fourteenth 53 00:03:09,040 --> 00:03:12,440 Speaker 1: is also Albert Einstein's birthday, making Pie Day a nerd 54 00:03:12,480 --> 00:03:16,079 Speaker 1: double header. The first Pie Day celebration was nothing more 55 00:03:16,120 --> 00:03:18,560 Speaker 1: than Shaw and his wife handing out slices of fruit 56 00:03:18,600 --> 00:03:22,519 Speaker 1: pie and tea at one pm one f nine being 57 00:03:22,560 --> 00:03:25,520 Speaker 1: the three digits following three point one four, but the 58 00:03:25,520 --> 00:03:29,639 Speaker 1: holiday quickly gained fame in the Bay Area. Shaw eventually 59 00:03:29,639 --> 00:03:33,480 Speaker 1: built the Pie Shrine at the Exploratorium, a circular classroom 60 00:03:33,520 --> 00:03:37,000 Speaker 1: with a circular brass plaque at its center. Every Pie 61 00:03:37,080 --> 00:03:40,200 Speaker 1: Day celebration at the Exploratorium ended with a colorful parade 62 00:03:40,360 --> 00:03:42,960 Speaker 1: led by Shaw blasting his boombox with a remix of 63 00:03:43,000 --> 00:03:45,600 Speaker 1: Pomp and Circumstance set to the digits of Pie and 64 00:03:45,800 --> 00:03:49,440 Speaker 1: circling the Pie Shrine exactly three point one four times. 65 00:03:50,200 --> 00:03:52,440 Speaker 1: The parade ended with the singing of Happy Birthday to 66 00:03:52,480 --> 00:03:56,520 Speaker 1: Albert Einstein. The Prince of Pie passed away in twenty seventeen, 67 00:03:56,800 --> 00:04:00,200 Speaker 1: but the annual Exploratorium party continues, as do Pie Day 68 00:04:00,200 --> 00:04:04,080 Speaker 1: celebrations the world over. Popular ways to celebrate include baking 69 00:04:04,080 --> 00:04:07,360 Speaker 1: a pie or some kind of circular treat, and holding 70 00:04:07,640 --> 00:04:11,760 Speaker 1: pie recital contests. The current world record for memorizing and 71 00:04:11,800 --> 00:04:14,920 Speaker 1: reciting the most digits of pie was set by Hiresh 72 00:04:15,000 --> 00:04:18,520 Speaker 1: Kumar Sharma of India in twenty fifteen, when he recited 73 00:04:18,560 --> 00:04:22,520 Speaker 1: a staggering seventy thousand and thirty digits in seventeen hours 74 00:04:22,520 --> 00:04:26,480 Speaker 1: and fourteen minutes, but it's okay to start somewhere below that. 75 00:04:27,279 --> 00:04:30,440 Speaker 1: Producer Tyler says that at one point back in the 76 00:04:30,480 --> 00:04:32,680 Speaker 1: day he had about a hundred and fifty memorized, but 77 00:04:32,839 --> 00:04:38,040 Speaker 1: right now can do around eighty three point one two, six, five, eight, nine, seven, four, six, 78 00:04:38,040 --> 00:04:39,640 Speaker 1: two six, four three three eight, three two seven, nine, 79 00:04:39,680 --> 00:04:42,920 Speaker 1: five zero two eight, four, one six, nine, three nine seven, zero, 80 00:04:42,920 --> 00:04:44,480 Speaker 1: five eight, two zero, nine, seven four and four for 81 00:04:44,600 --> 00:04:46,520 Speaker 1: five nine, two, three, zero, seven, eight, one six, four zero, 82 00:04:46,560 --> 00:04:53,760 Speaker 1: six three six y. Today's episode was written by Marshall 83 00:04:53,760 --> 00:04:56,680 Speaker 1: Brain and Dave Ruse and produced by Tyler Clay. For 84 00:04:56,760 --> 00:04:58,839 Speaker 1: more on this and lots of other curious topics, visit 85 00:04:58,880 --> 00:05:01,520 Speaker 1: hastaff works dot com. Brainstuff is a production of I 86 00:05:01,600 --> 00:05:04,120 Speaker 1: heart Radio. For more podcasts for my heart Radio, visit 87 00:05:04,120 --> 00:05:06,680 Speaker 1: the iHeart Radio app, Apple Podcasts, or wherever you listen 88 00:05:06,720 --> 00:05:07,560 Speaker 1: to your favorite shows.