WHAT IS PI?

It is long time since PI was introduced, William Jones introduced it in 1706, and we know that we use PI to find areas and circumference of any Circular object. The symbol of PI which is “π” was popularized by Leonhard Euler in 1737.  But what is that PI? And how was it obtained?

ACTIVITIES:

(i)  Collect circular objects such as  pots, bottle tops, bangles, cups, mugs, bucket covers  and the like. See the picture below:

(ii) Take a tape measure:

(ii) Measure the circumference as shown below: (record down every data you obtain)

(iii) Measure the diameter as shown below: (record down every data you obtain)

(iv) Divide the circumference of each object by its corresponding diameter that is:

 (Circumference ÷ Diameter) in short  ^C/_D , The answer will be PI (3.14) for any object.

Ally collected five different circular objects and conducted the following experiment:

1: He obtained the circumference of the cup 18.85cm and Diameter of the same cup 6cm then he  divided  18.85cm by 6cm he got  3.14 (corrected to two decimal places)

2: He obtained the circumference of the bangle 39.3cm and Diameter of the same bangle  12.5 cm then he  divided  39.3cm by 12.5cm,  he got 3.14 (corrected to two decimal places)

3: He obtained the circumference of the bottle top 9.4cm and Diameter of the same bottle top  3cm then he  divided  9.4cm  by 3cm, he got 3.14 (corrected to two decimal places)

4: He obtained the circumference of the glass   22cm and Diameter of the same glass 7cm then he divided 22cm divide by 7cm, he got 3.14 (corrected to two decimal places)

5: He obtained the circumference of the steering wheel   119.4cm and Diameter of the same steering wheel   38cm then he divided 22cm divide by 7cm, he got 3.14 (corrected to two decimal places)

If you observe carefully the results of the experiment, you will find that all fell at 3.14 which is the approximation of PI. And that is how PI was introduced and used to find Circumference and Area of any circular object

CONCLUSION:

PI is approximated to 3.14, it is an irrational number and it is also written approximately as fraction as ²²/₇.  But remember the closer approximation of PI in fraction is  ³⁵⁵/_113. 
By dedinition: PI is the ratio of the circumference to the Diameter.

Therefore: PI = 3.14 or ²²/₇