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!