# The History of Pi

Pi. Not to be confused with pie, the delicious dessert filled with cinnamon spiced apples or gooey cherries, the number pi proves a powerful tool in the realm of mathematics. Pi, or 3.14159, is an irrational number commonly used in geometry to determine the circumference or area of circles and spheres and plays a fundamental role in mathematics. You have probably seen pi crop up in area, volume and circumference formulas such as the area of a circle (pi*r^2), the circumference of a circle (2*pi*r), and the volume of a sphere ((4/3)*pi*r^3). Although the number is named after a Greek letter, civilizations before the Greeks knew of its geometric power. The kingdom of Israel under Solomon, for instance, already had an understanding of pi in relation to circles. In Melachim Aleph (Kings I), many descriptions of the vessels in Solomon’s temple are described in detail. While describing one of the temple’s basins, known as the “molten sea,” the number pi is hinted to. The verse states: “And he made the molten sea, ten cubits from brim to brim; it (was) round all about, and the height thereof (was) five cubits; and a line of thirty cubits did compass it round about” (Kings I, 7:23). Here the mouth of the basin is described as being 10 cubits in diameter, and 30 cubits in circumference. In other words, the Jews during Solomon’s time seem to have had an understanding that a ratio exists between the diameter and circumference of a circle. They estimated the constant ratio between these two values to be 3, as the circumference divided by the diameter for Solomon’s basin is 30 cubits divided by 10 cubits, or 3. Although 3 is not the exact value of pi, it is quite impressive that Jews under Solomon’s rule noticed such a ratio. It is no less surprising that the prophet who wrote Melachim Aleph found the rough ratio important enough to include in his writings. This just goes to show how holy math can be!

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