# The Story of π: A Mathematical Journey through Time

## Pi: A Fascinating Journey Through Time and Mathematics

How did we found the value of π ?

Pi, the mathematical constant that represents the ratio of a circle’s circumference to its diameter, has fascinated mathematicians for centuries. Pi is used to calculate the circumference and area of circles and spheres, which are present in many objects around us, including wheels, balls, and cylindrical containers. In engineering, pi is used to design and build structures, such as bridges and buildings, that require circular shapes and curves.

Pi is also used in physics to calculate the frequencies of sound waves and the orbits of planets. For example, the formula for calculating the period of a pendulum, which is used in clocks, involves pi. Additionally, pi is used in geometry to calculate the volume and surface area of cylinders, cones, and other three-dimensional shapes.

In our daily lives, pi can be found in many places, such as clocks, watches, and measuring tools. For instance, a clock with a circular face relies on pi to keep accurate time, as the length of each second hand rotation is determined by the circumference of the clock face. Similarly, measuring tools such as rulers and tape measures use pi to measure circular objects accurately.

Its value has been studied, explored, and refined by brilliant minds throughout history. In this article, we will take a journey through time and explore the history of pi, its significance, and how mathematicians have arrived at its accurate value.

### The First Recorded Calculation of Pi

As we have seen, the ancient Babylonians were the first to make a recorded calculation of Pi. However, they were not the only civilization to attempt to understand the value of Pi. The ancient Egyptians also approximated Pi in order to construct their famous pyramids. The Rhind Mathematical Papyrus, a collection of ancient Egyptian mathematical texts, contains a problem that asks for the area of a circle with a diameter of nine units. The solution involves approximating Pi as 3.16.

In the 5th century BC, the Chinese mathematician Zu Chongzhi (429 B.C. to 501 B.C.) calculated pi to be between 3.1415926 and 3.1415927. In the 3rd century BC, the Indian mathematician Aryabhata calculated pi to be around 3.1416.

### The Quest for the Accurate Value of Pi

The Greek mathematician Archimedes, who lived from approximately 287 BC to 212 BC, used a geometric method to calculate that pi was between 3.1408 and 3.1429. Archimedes’ method involved inscribing and circumscribing circles with regular polygons. By increasing the number of sides of the polygons, he was able to approximate the value of pi more accurately.

In the 14th century AD, mathematician and physicist Madhava of Sangamagrama, from Kerala, India, developed a series for Pi, using the trigonometric functions sine and cosine. This series is now known as the Madhava-Leibniz series and is considered a precursor to calculus. Later, in the 17th century, the English mathematician John Wallis developed a similar series that could be used to calculate Pi to any desired degree of accuracy.

In the 14th century AD itself, the Persian mathematician Jamshīd al-Kāshī calculated pi to 16 decimal places, which was the most accurate value of pi at the time. He used a polygon with 3.2 million sides to arrive at this value.

The European mathematicians of the 16th and 17th centuries continued the quest for the accurate value of pi. The German mathematician Ludolph van Ceulen was one of the most notable pi calculators of this time. He spent his entire life calculating pi to 20 decimal places, and his gravestone even has the first 20 digits of pi inscribed on it.

### The Accurate Calculation of Pi

In the 18th century, Johann Lambert calculated Pi to 20 decimal places, making it the most accurate calculation to date. In the 19th century, the French mathematician François Viète discovered a formula that could be used to calculate pi to an arbitrary number of decimal places. This formula was later refined by John Machin, who used it to calculate pi to 100 decimal places in 1706.

The credit for introducing the greek letter π was goes to the Welsh mathematician William Jones. However, the symbol did not gain widespread acceptance until it was adopted by the Swiss mathematician Leonhard Euler in the mid-18th century. In 1844, the mathematician William Rutherford calculated Pi to 208 decimal places, which was a significant achievement at the time.

In the 20th century, the advent of computers revolutionized the calculation of pi. In 1949, ENIAC, one of the first electronic computers, was used to calculate pi to 2,000 decimal places. The mathematician John von Neumann developed a new method for calculating Pi using a Monte Carlo method. This method involves using random numbers to approximate the area of a circle and the square it is inscribed in. By repeating this process many times, an increasingly accurate estimate of Pi can be obtained.

### The Most Accurate Calculation of Pi

In 1986, the Chudnovsky brothers, David and Gregory, used a supercomputer to calculate pi to an unprecedented 2.7 billion decimal places. This was a significant milestone in the quest for more accurate and precise values of pi. The brothers developed a new algorithm for computing pi that was based on their work in number theory and the theory of elliptic curves. Their algorithm was highly efficient and allowed them to break the previous record for computing pi by several orders of magnitude.

Today, the value of pi is known to an incredibly high degree of accuracy, thanks to the development of advanced mathematical and computational methods. The most accurate calculation of Pi was performed by Emma Haruka Iwao, a Google employee, who used Google’s cloud computing platform to calculate pi to 31.4 trillion digits in 2019. This is a truly remarkable achievement that demonstrates the incredible power of modern computing.

Did you know that Pi Day is an annual celebration held on March 14th (3/14) to honor the mathematical constant pi (π)? Pi Day was first recognized by physicist Larry Shaw in 1988, who organized a Pi Day celebration at the San Francisco Exploratorium where he worked. Since then, Pi Day has become a global celebration of pi, with events held in schools, universities, and communities around the world. Pi Day is often celebrated with pi-themed activities, such as reciting the digits of pi, eating pi-themed foods like pie, and participating in math and science activities related to pi.

https://en.wikipedia.org/wiki/Pi_Day

The history of the value of Pi is a fascinating journey through the centuries, with contributions from many brilliant mathematicians and civilizations. The accurate calculation of Pi was a significant challenge that required the development of new mathematical methods and the use of advanced computational tools. Today, Pi continues to be an important concept in mathematics and is used in many fields, from engineering to physics to computer science.