ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Pi & the Circumference of a Circle, Easy Project for Visual Reinforcement.

Updated on February 7, 2018
Supplies gathered
Supplies gathered
I placed my finger in the center of the cd in order to hold it in place while I traced
I placed my finger in the center of the cd in order to hold it in place while I traced
cut out the circle
cut out the circle
one perfect circle ready for the project
one perfect circle ready for the project
unfold to find center point
unfold to find center point
my radius is 2 3/8 inches
my radius is 2 3/8 inches

3.14159..... March 14 is Pi Day. As a math teacher I make a point to celebrate pi day with learning and not with pie. I refuse to acknowledge the relationship between the two in order to have a sweet treat in math class.

Here is what I do instead.

I use March 14 as an exploration of why pi exists and how we can find the circumference of a circle using what we know.

Materials Needed

One circle of each student (depending on the age group you may want to give them the circle and the center may need to be marked)

Scissors

Rulers

Writing utensils

A thirst for knowledge

Objective: To find the circumference of a circle without using pi. Show that pi does help find the circumference of the circle.

For this project I needed a circle so I traced a cd onto a piece of paper and cut it out.

I was able to easily find the center of my circle by folding the circle in half twice. The intersection of the two points creates the center point. I marked this with a pen.

Measure the radius of the circle. Write this number down somewhere important, we will need it later. We are going to divide our circle in to several sections using the center of the circle to that we are dividing the circle into equal sections through the center creating multiple radius sections.

I am going to cut my circle into 16 separate sections. The more sections you divide you circle into the more exact the answer will be for finding the circumference. I am going to cut my circle into each section.

I was able to easily divide my circle but repeatedly folding in half. Once I opened the circle I used a ruler to draw the sections.

I then cut the sections apart.

Now that I have all my sections cut out I am going to create a "rectangle" with all the pieces. By laying the pieces down every other way we are able to create an almost rectangle. Remember I said the more pieces you cut into your circle into the more precise it will be. if I had double the number of pieces in this part it would look even more like a rectangle.

I am going to attempt to measure each side of the rectangle. Think about the shape of the circle. Remember that the width of the rectangle is the radius of the circle while both of the lengths of the rectangle add together to make the entire circumference.

So let's go back to the measured radius at the beginning. The formula for circumference is 2r∏.

let's estimate just to make this easy. Radius = 2.375

2 * 2.375 * 3.14 is approximately equal to 14.91

The side of the rectangle is approximately 7.5. there are two sides so add them together 7.5+7.5 = 15 or 7.5 *2 = 15.

Notice that the sides of the rectangle add to the approximate circumference for the circle.


Have your students talk about how the circumference and the length are related. This is a great exploration activity that work well in a geometry unit or simply to talk about pi on Pi Day.

Another extension activity is to use string and measure around cylindrical objects, find the radius and calculate the circumference and measure the string.


Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      debajyoti panday 

      3 years ago

      the problems are beautiful.

    • profile image

      Richard Thiessen 

      5 years ago

      I liked what you did in your this post, but you confused me for a minute because I thought you were going to focus on area. I've never thought to use these sectors of the circle to think about circumference and the meaning of pi. Very nice!

    • kthix10 profile imageAUTHOR

      kthix10 

      6 years ago from IL

      All the schools I have worked at have outlawed the practice of eating pie on pi day due to health standards and nutrition. Of course my last headmaster also wanted to ban birthday treats but that is another story

    • Wise fool profile image

      Jennifer Missen 

      6 years ago from Colorado

      I love pi day. My son gets to eat pie at school. It's a fun party.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)