It looks like this,… Not like this,…
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Transcript of It looks like this,… Not like this,…
March 14 isNational
Pi Day
What is pi?
Pi is a math
symbol
It looks like this,…
Not like this,…
We use
pi in
Geometr
y
to find the area and
circumference of a circle
Pi means
exactly
22/7
…but we round pito 3.14
Do you know why we
celebrate National Pi Dayon March 14?
…because it
is also a
famous
person’s
birthday,…
Albert Einstein
He was a very
famous scientist
and
mathematician.
He did a lot of
stuff and was
really, really,
REALLY smart!
Referring to his birthday as
“Pi Day” is a good way to
honor his memory!
3.14Get it?
Pi Day is celebrated on March 14th (3/14)
around the world.Pi is the word for the
Greek letter “π.”
Pi has been calculated to over one trillion digits beyond its
decimal point. As an irrational number, it
will continue infinitely without repetition or
pattern.
Let’s learn
some things
about pi,
…
By holding hands and making a circle, these children are demonstrating circumference.
Let’s practice,…C=πdC=3.14x8C=25.12
So, the circle’scircumference is 25.12cm.
(diameter)(8
centimeters)
Now you try,…A circle has a diameter of 10 centimeters. What is the circumference?
C=πd
C=πd
C=3.14x10
C=31.40
So, the circle’scircumference is
31.40cm.
Pi is pretty cool, but you can do more than just
find the circumference.
You can use pi to find
the area of a circle
too!
But what is area
you ask?
Area is all of the
“filling” on the
inside of a
shape.
It is kind of like finding out how
much new carpet you
would need for your bedroom.
So how do we
use pi to find
out the area of
a circle?
First, you need
to know the
radius of the
circle.
What is
a
radius,
you ask?
A radius
is HALF
of the
diameter.
It takes
2 radii
to make
1
diameter
.
Let’s practice,…
A=πr2
A=3.14x62
A=3.14x6x6
A=113.04cm2
So, the area of the circle is 113.04cm2.
6 cmradius
Now you try,…A circle has a radius of 4 centimeters. What is the area of the circle?
A=πr2
A=πr2
A=3.14x42
A=3.14x4x4A=50.24cm2
So, the area of the circle is 50.24cm2.
Pi is not that
hard to use in
an equation!
You just have
to know the
circle’s “slices”
and then
multiply.
Diameter
&
Radius
It is not
that hard!
Pi
Anybody can
learn to use pi!