What is really Pi?

Question

What is this value 22/7 and why does it appear in so many scientific formulas. Is it a magic number or what? Please i really want to understand

Answer 1

Great question. Most simply, π is the ratio of a circle's circumference to its diameter (this ratio is the same for every circle, big or small).



It is not exactly equal to 22/7; that is just an approximation of the true value of π. An even closer approximation is 355/113. But actually, there is NO fraction that is EXACTLY equal to π.



You're correct that it appears in many scientific formulas that seem to have nothing to do with circumferences and diameters of circles. This is curious! But the fact is, most of these formulas usually do have something to do with relating angles and straight lines; so there is something "circular" about them.



For example, there's a famous equation that shows the distribution of speeds of molecules in a gas, and that equation has π in it. If you examine the equation closely, the π comes from considering all the different angles at which the molecules can move. So again, when something relates angles and straight lines, π often pops up.

Answer 2

The value of Pi is *not* 22/7, it is the ratio of the circumference of a circle to its diameter. 22/7 is just a close approximation of Pi. It is a magic number, like the natural log base 'e'.

Answer 3

Though Pi isn't magical, it is mystical. The value of Pi has been known for millennia, and the Bible approximates it as 3. It is and shall always be an essential ingredient in any fundamental mathematics that attempts to reveal through physics and science the myriad wonders of life and reality. It is the most familiar of the mathematical 'constants' we call 'irrational numbers', meaning numbers that are unending and non-repeating and, thus, it can't be represented as the 'ratio', or 'fraction', of two integers (1, 2, 3, etc.).

Whereas Pi = 3.141529... (non-repeating; unending), the fraction 22/7 = 3.14285714285714... in which the last six digits, 285714, repeat ad infinitum. In other words, 22/7 is a simple fraction which feigns to help students remember the approximate value of Pi for basic calculations, and using it as such will result in mathematical answers only accurate to three significant digits. Since the student must also remember that it's only accurate to two decimal places, it would be better if the student just remembered 3.14.

A much more accurate mnemonic for Pi's value is represented by a simple, poetic verse that, though brief in length, forges in depth Pi's value to an accuracy of 11 decimal places and reveals in its breadth the first great mind to winnow and expound Pi's secrets, the Greek mathematician, Archimedes of Syracuse. It goes as follows:

How I Wish I Could Determine, Of Circle Round, The Exact Relation Archimedes Found.

If you count the number of letters in each word of the verse except the last, you arrive at Pi to 11 decimal places, 3.14192653589, well outside the accuracy needed for most school work.

Answer 4

The value Pi is a relationship between the radius of a circle and its circumference. For any circle, this is the same fixed number. It is a property of a circle. The circumference, c, divided by the radius x 2, r, ( or the diameter) = pi. It so happens that pi itself is one of the category of numbers called transcendental, meaning it cannot be fully and completely expressed as a decimal. It is a little more than 3.14. It's not really magic, but it is mystical.

Answer 5

For a quick and dirty definition of Pi:



Take a circular object such as a tomato can, measure the distance across (known as the diameter). Now measure the distance around the can (known as the circumference). This can be done with a flexible ruler such as a tape measure.



The ratio of circumference / diameter will always produce a value of pi or 3.14159....... You won't get exactly this number due to inaccuracies in your measurement but you will come close. In equation form C = Pi*D or solving for Pi: Pi = C / D



Because this ratio of C / D will always produce the same number, Pi is known as a geometric constant.



If you look up Pi on google you will also probably find where it can be defined in terms of natural logarithms or "e".



It's used quite a bit in science and engineering.

Answer 6

Pi is the ratio between the circumference of a circle and it's diameter

it is an irrational number 3.14 is the abrivation..it goes on for ever

22/7 is the closest to that value

Answer 7

Pi is a mathematical constant and a real number, with many uses in mathematics, physics, and engineering. And Pi is the ratio of the circumference of a circle to its diameter.

Answer 8

the value 22/7 is a very crude approximation. pi is actually the ratio of the circumference of a circle to its diameter.it can be shown that for any circle this ratio is constant.