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We have had some knowledge of our number systems and have realised how important Zero is.

Meanwhile, there is another special number that very much needed in Mathematics. The number that is very much needed in mathematics. The number is 𝛑 ( pronounced as pie in English).

This number 𝛑 is the lowercase of a Greek letter and it is derived from the first letter of the Greek word ‘perimetros’, meaning circumference (the distance around something).

When we use the word ‘circumference’ in Mathematics, it means the length of the edge around a curved geometric figure, especially a circle.

From the above, it is possible to calculate the length or distance around a circle. We can also join two points on the circle and measure their length. Joining different pairs of points on the circle will give different lengths.

In this case there will be a line with the highest length. This is the line that joins two points on the circle through the centre or midpoint of the circle. This line is called the diameter. Half of the diameter, or the length from the midpoint to any point on the circle is known as the radius.

At this stage, we can find the relationship or ratio between the distance around a circle (circumference) and the distance from one point on the circle to another through the midpoint (diameter).

This is the ratio of the circumference and the diameter and that is what the number 𝝿

Represents. Surprisingly, the ratio of turns out to be the same for any circle, no matter how big or small it is.

You can try calculating 𝛑 by searching for any circular objects of different sizes. Find the circumference of each item by using a tape measure to wrap around it, and then find the diameter by measuring across the widest part with a ruler. Next divide the circumference by the diameter. Since no one can measure perfectly, you will not get the exact answer each time.

However, you should find that the ratio is around 3.1 and 3.2, no matter the size of the circle you measure.

Examples of some measurements can be seen in the video below.

The value of 𝝿 (Pi) continues to infinity. Computer scientists have calculated billions of digits of Pi, starting with 3.14159265358979323……….However, since no recognisable pattern emerges in the succession of its digits, it turns out to be an irrational number. This means its exact value cannot be known and thus an approximation was needed.

Ancient Babylonians gave a approximation of 3. Nevertheless, this is not as close to 3.1415 as the fraction 22/7 which is equal to 3.142857.

The acceptable value was established by computers and till this day the value for Pi is 3.14 or 22/7.

The video below shows some facts about the history of 𝝿 from THE EVERYTHING KIDS MATHS


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