What is Pi?Pi is a letter in thegreek alphabet, but itis used to represent theratio of thecircumference of acircle to its diameter.Pi looks like this: π
Being an irrational number Pi is an irrationalnumber which meansthat its exact numberwill never be knownbecause the number justgoes on and on.Also pi’s numbers are ina random order andnever are in a pattern.
VocabularyHere are some examples of words you should know whenyou are dealing with pi:Radius= a straight line extending from the center of acircle to a point in the circumference of the circleDiameter= a straight line passing through the center ofa circle which is connecting two points in thecircumferenceCircumference= the outer boundary line of a circleArea= the amount of space inside a flat object such as acircle or a rectangle.
How pi is usedPi can be used to findthe circumference of acircle by using theformula shown below.In the formula:c=2•π•r c=circumference π=pi r=radius
ExampleExample: The radius of a circle is 3.What is its circumference?Solution: C=2•π•r r=3 cm C=2•π•3 cm C=6 cm•3.14 C=18.84 cm
How pi is used #2Another way pican be used isto find the areaof a circle byusing thisformula: 2 a=areaa=π•r π=pi 2 r =r squared
ExampleExample: The radius of a circle is 5 cm.What is the area of the circle? 2Solution: a=π•r2 a=π•5 cm r=5 cm a=π•25 cm a=3.14•25 cm a=78.5 cm
How pi is used #3You can also use pito find the volumeof a cylinder byusing thisformula: 2 v=volumev=π•r •h π=pi r =radius h=height
ExampleExample: The radius of this cylinder is 2and its height is 4. What is its volume? 2Solution:v=π•r •h r=2 2 v=π•2 •4 h=4 v=π•4•4 v=π•16 v=3.14•16 v=50.24
The Beginning of Pi The first recorded equation of pi was about 4,000 years ago from the Babylonians and the Egyptians. The number they got was close to pi, but not completely accurate. Babylonians thought that pi was 3.125 Egyptians thought that pi was 4
More HistoryMany other cultures hadknown about the significanceof pi and had gotten a roughestimate like:The Hebrews thought it was 3as well as the Chinese. TheTorah mentions the presence ofpi. They had greatmathematicians such as ZuChongzhi who were able to get arange of where pi is.
How pi is used in our daily worldPi is so important because ithelps use find the area andcircumference of a circle.Because it can do this, thenit can help us in a lot ofother things such as scienceand architecture andeverything because circlesand spheres are in our dailylife.
Extra things about piSince pi is such a big "Slices of Pi" -author unknownpart of our lives we even No one will find a pattern in pihave a special day for it This number has come out of nowhereon March 14 All one can do is close a book and sigh You should be able to tell with your eye A rhythym here isnt fairIn this day people do This number can make a simple brain fryfun things with pi like Though there are those who dont care And dont give it a thought or a sigh!write poems or make So, many a person will surely trysong or make pi t-shirts There are many who have dared But no one will find a pattern in pi A bottomless pit, unconquered and dry An unexplainable tear A satisfactory conclusion is a sigh Since no one will find the (do you see it?) the pattern in pi...