Description
Pi Day. The number pi is a mathematical constant. Originally defined as the ratio of a circle's circumference to its diameter, it now has various equivalent definitions and appears in many formulas in all areas of mathematics and physics. Pi is commonly defined as the ratio of a circle's circumference C to its diameter d. The ratio C/d is constant, regardless of the circle's size. For example, if a circle has twice the diameter of another circle it will also have twice the circumference, preserving the ratio C/d.

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pi-symbol-for-pi-day, math, spiral, pi-symbol, pi-number