Probably no figure in science has evoked so much mystery, romance, misconception and personal interest as the very popular number pi. Pi (sometimes written with the Greek letter pi) is the irrational number that lies between zero and the circumference of a complete circle.
This number is also known by many other names, including the Greek letter Phi, the Roman number e, and the Chinese letter Chi. In Europe, pi is known better as the fraction whose digits add up to the same number formed by the sum of all the other digits.
The reason why many people know (or know their way around) this irrational number Pi is that it is one of the fundamental components in many mathematical theories. For example, every sphere and hemisphere on which the sun shines is equated with the number e; thus the circumference of the earth is also the sum of the radii on each side of the equator. The diameter of an object also determines its weight, whereas the mean value of a number (pi) is not determined by any object at all. This definition of a mathematical constant can be expanded to a more general notion known as a “pi” or “number pi”.
One of the first questions that will come to your mind when you hear about pi is what it actually is. The short answer to this question is that pi is a transcendental number, one that cannot be expressed in the finite world of regular algebra. While many people understand that pi is a real or irreducible entity that cannot be compared to any other objects in our physical universe, many others are left completely mystified by what exactly this entity is.
The closest thing that we have ever been able to measure is the diameter of the earth, a measurement that was made possible by satellite mapping in the 1970s. The problem with this measurement however is that it only measures the inner diameter of the earth and does not include any of its satellites. Thus, the surface area of the earth is actually much greater than the surface area of the moon, which means that it would make no sense to map the moon on the earth using the same metric. Is the moon round? Are there other satellites in our solar system? These are the types of questions that remain unanswered because they are unanswerable by traditional mathematics.
The diameter of the circle is not the only thing that cannot be directly measured, because the circumference of the circle is not a multiple of the diameter of the earth. For example, if a person were to draw a circle on a square graph, and were to include the width of their circle at the top of their graph, and the circumference of their circle at the bottom, they would find that the inner and outer diameters of their graph would not add up to the total diameter that was measured. To determine the circumference of a circle, you must multiply the diameter by the ratio of its circumference to its diameter, which is exactly what you would do if you were to measure the diameter of the earth. Thus, the reason why PI can never be directly compared to the diameter of the earth is that the circumference and diameter of the earth are unrelated, and PI is a value derived from a calculation that has nothing to do with the size of the earth.
How is PI defined? PI is the ratio between any two circular objects, and it was first defined by the ancient Babylonians. The circle was chosen specifically because of its perfect circular shape, and the Babylonians knew that adding a third object to the circumference of the first object would effectively alter the shape of the second object, and the third would result in an image of the earth-orbit around the sun. This knowledge had great significance to the early Egyptians, who could calculate the circumference of the earth by understanding the basic geometric ratios of the planet’s orbit. The Egyptians also figured out the ratio between the diameter of the earth and the distance between the North Pole and the South Pole, and this they believed to be the key factor of time.
Calculating PI involves lots of digits and a calculator, but let’s start at the beginning: the circumference of the earth is actually about 6,bug circumference. The real value of PI, as we’ll see shortly, is actually derived from other measurements. It is derived from the actual circumference, and diameter, of the moon, and the solar system, and all the other celestial bodies out to a very great distance. These other measures all have to be expressed in radians, and so the formula for computing PI simply uses r, the angle between the latitude and longitude, the semi-axis, and the cube root of the cosine formula (cos(pi) / sin(pi).
When we finally reach the digits, however, PI is expressed as the formula tan(r) where r is the radii, and c is the diameter of the earth. It turns out that the calculation of PI can be done using only about four thousand years of data, using data that is available to mathematicians from the Stone Age to the contemporary era. Today, it takes less than a second to solve a simple problem involving pi, and the fact that many computers contain powerful enough computers to do so makes it possible for a student to do real work using a computer.