Advertisement.

EnchantedLearning.com is a user-supported site.
As a bonus, site members have access to a banner-ad-free version of the site, with print-friendly pages.
Click here to learn more.

ad
(Already a member? Click here.)


Our subscribers' grade-level estimate for this page: 3rd - 4th

+, -
EnchantedLearning.com
Math Lessons and Worksheets
x, ÷
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Counting Addition Subtraction Multiplication Division
Number Line Fractions Decimals Measurement Rounding Graphs
Pi Math
What is Pi?
pi piPi (π) is a number that is roughly equal to 3.14159. Pi is the ratio of the circumference (perimeter) of any sized circle to its diameter. No matter what sized circle you have, the ratio of its circumference to its diameter is always the same -- pi. For example, when a circle's diameter is 1, its circumference is π. When a circle's diameter is 2, its circumference is 2 times π.

Pi is Irrational
Pi is an irrational number. This means that pi cannot be written as a fraction of two whole numbers and that the decimal digits of pi continue infinitely without any repeating pattern. Pi is roughly 3.14159265358979323846.... Using computers, pi has been calculated to many million of digits past the decimal point. For many purposes, using the approximation 3.1416 is sufficient. Good approximations for pi are 22/7 and 355/113.

Formulas
Pi is used in many calculations, including finding the circumference and area of a circle, and the volume and surface area of a sphere, cone, and cylinder. Pi is also used in geometry, probability and statistics, and many other fields.

Circumference Area
piCircle
(radius = r)
2π r π r2


Surface Area Volume
piSphere
(radius = r)
4π r2 (4/3) π r3
pi
Cylinder
(radius = r, height = h)
2π r h (without the ends) π r2 h

The Name Pi
Mathematicians began using word pi (the Greek letter π) for this ratio in the early 1700s; the name pi was given to this number because p is short for perimeter.

Pi Day
Pi Day is a mathematical holiday celebrated by math classes on March 14th (3/14), with the peak celebration occuring at at 1:59 p.m (3/14 1:59). Pie, pizza, and other round foods are often served at Pi Day celebrations.

Pi-Related Worksheets:
find related words

Write Eight Round Things

Think of and write eight round things. Then, for each word, write a sentence containing the word. Sample answers: pie, disk, pie plate, necklace, plate, circle, wheel, pupil of the eye.
find related words

Write Eight Round Things in Categories

Think of and write eight round things in categories, including: food, sports item, school item, household item, animal, article of clothing, part of a vehicle, astronomical object. Then, for each word, write a sentence containing the word. Sample answers: pizza, basketball hoop, globe, plate, sand dollar, bracelet, steering wheel, moon.
Draw Four

Draw Four Round Things

Draw four round things. Below each item, write its name.
Draw Four

Draw Four Spherical Things

Draw four spherical things. Below each item, write its name.
calculating pi

Calculating Pi
A Printable Worksheet

In this worksheet, the student measures the circumference and diameter of three circles, and then calculates the ratios of the circumferences to the diameters (approximating pi). The student will need a ruler and a short length of string or yarn (a bit less than a foot long); the yarn is used to measure the circumferences. Or go to the pdf version.
What is Pi

What is Pi?
A Printable Worksheet

A printout about what pi is. Measure the circumference and diameter of four printed circles, then determine what relationship between the circumference and the diameter gives a constant value (pi). This printable worksheet demonstrates to the student that pi is the ratio of a circle's circumference to diameter, for any circle The student will need a ruler and a short length of string or yarn (a bit less than a foot long); the yarn is used to measure the circumferences. Or go to the pdf version.
All-Purpose Check-Off Card

Check-Off Card

Print a card that is good for many occasions, including Happy Birthday, Valentine's Day, Mother's Day, Father's Day, Congratulations, Graduation, Get Well Soon, Pi Day, Easter, Christmas, Hanukkah, Ramadan, Anniversary, New Year or Many Thanks. Just print the card, then check off the appropriate occasion.
Europe map to label

Label Lower-case Greek Letters

Label the lower-case Greek letters.
Answers

+, -
EnchantedLearning.com
Math
x, ÷
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Counting Addition Subtraction Multiplication Division
Number Line Fractions Decimals Measurement Rounding Graphs


Enchanted Learning®
Over 35,000 Web Pages
Sample Pages for Prospective Subscribers, or click below

Overview of Site
What's New
Enchanted Learning Home
Monthly Activity Calendar
Books to Print
Site Index

K-3
Crafts
K-3 Themes
Little Explorers
Picture dictionary
PreK/K Activities
Rebus Rhymes
Stories
Writing
Cloze Activities
Essay Topics
Newspaper
Writing Activities
Parts of Speech

Fiction
The Test of Time

Biology
Animal Printouts
Biology Label Printouts
Biomes
Birds
Butterflies
Dinosaurs
Food Chain
Human Anatomy
Mammals
Plants
Rainforests
Sharks
Whales
Physical Sciences: K-12
Astronomy
The Earth
Geology
Hurricanes
Landforms
Oceans
Tsunami
Volcano
Languages
Dutch
French
German
Italian
Japanese (Romaji)
Portuguese
Spanish
Swedish
Geography/History
Explorers
Flags
Geography
Inventors
US History

Other Topics
Art and Artists
Calendars
College Finder
Crafts
Graphic Organizers
Label Me! Printouts
Math
Music
Word Wheels

Click to read our Privacy Policy

E-mail


Enchanted Learning Search

Search the Enchanted Learning website for:



Advertisement.

Advertisement.


Copyright ©2008-2018 EnchantedLearning.com ------ How to cite a web page