2. What is Pi?
Pi is a letter in the
greek alphabet, but it
is used to represent the
ratio of the
circumference of a
circle to its diameter.
Pi looks like this: π
3. Being an irrational
number
Pi is an irrational
number which means
that its exact number
will never be known
because the number just
goes on and on.
Also pi’s numbers are in
a random order and
never are in a pattern.
4. Vocabulary
Here are some examples of words you should know when
you are dealing with pi:
Radius= a straight line extending from the center of a
circle to a point in the circumference of the circle
Diameter= a straight line passing through the center of
a circle which is connecting two points in the
circumference
Circumference= the outer boundary line of a circle
Area= the amount of space inside a flat object such as a
circle or a rectangle.
5. How pi is used
Pi can be used to find
the circumference of a
circle by using the
formula shown below.
In the formula:
c=2•π•r c=circumference
π=pi
r=radius
6. Example
Example: 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
7. How pi is used #2
Another way pi
can be used is
to find the area
of a circle by
using this
formula:
2 a=area
a=π•r π=pi
2
r =r squared
8. Example
Example: The radius of a circle is 5 cm.
What is the area of the circle?
2
Solution: a=π•r2
a=π•5 cm r=5 cm
a=π•25 cm
a=3.14•25 cm
a=78.5 cm
9. How pi is used #3
You can also use pi
to find the volume
of a cylinder by
using this
formula:
2 v=volume
v=π•r •h π=pi
r =radius
h=height
10. Example
Example: The radius of this cylinder is 2
and its height is 4. What is its volume?
2
Solution: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
11. 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
12. More History
Many other cultures had
known about the significance
of pi and had gotten a rough
estimate like:
The Hebrews thought it was 3
as well as the Chinese. The
Torah mentions the presence of
pi. They had great
mathematicians such as Zu
Chongzhi who were able to get a
range of where pi is.
13. How pi is used in our
daily world
Pi is so important because it
helps use find the area and
circumference of a circle.
Because it can do this, then
it can help us in a lot of
other things such as science
and architecture and
everything because circles
and spheres are in our daily
life.
14. Extra things about pi
Since pi is such a big "Slices of Pi"
-author unknown
part of our lives we even
No one will find a pattern in pi
have a special day for it This number has come out of nowhere
on March 14 All one can do is close a book and sigh
You should be able to tell with your eye
A rhythym here isn't fair
In this day people do
This number can make a simple brain fry
fun things with pi like Though there are those who don't care
And don't give it a thought or a sigh!
write poems or make So, many a person will surely try
song 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...
