Explaining The Universe on Instagram: "Pi (π) is a mathematical constant that represents the ratio of a circle’s circumference to its diameter. It is an irrational number, meaning its decimal expansion never ends or repeats, and its approximate value is 3.14159. Pi is one of the most important numbers in mathematics and science, appearing in countless formulas related to geometry, physics, and engineering. It is used to calculate the area and circumference of circles, the surface area and volume