K-12 Teaching and Learning From the UNC School of Education

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Important Message about LEARN NC

LEARN NC is evaluating its role in the current online education environment as it relates directly to the mission of UNC-Chapel Hill School of Education (UNC-CH SOE). We plan to look at our ability to facilitate the transmission of the best research coming out of UNC-CH SOE and other campus partners to support classroom teachers across North Carolina. We will begin by evaluating our existing faculty and student involvement with various NC public schools to determine what might be useful to share with you.

Don’t worry! The lesson plans, articles, and textbooks you use and love aren’t going away. They are simply being moved into the new LEARN NC Digital Archive. While we are moving away from a focus on publishing, we know it’s important that educators have access to these kinds of resources. These resources will be preserved on our website for the foreseeable future. That said, we’re directing our resources into our newest efforts, so we won’t be adding to the archive or updating its contents. This means that as the North Carolina Standard Course of Study changes in the future, we won’t be re-aligning resources. Our full-text and tag searches should make it possible for you to find exactly what you need, regardless of standards alignment.

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Related pages

  • Creating and understanding circles and their parts: This lesson will offer a hands-on opportunity to explore and construct circles. Students will develop a definition for identifying the parts of a circle such as the center, radius, diameter, chord, and circumference. Students will use compasses and rulers in constructing these parts of a circle.
  • Flying saucers: Circles: Students will apply what they have learned about circles and finding averages with this lesson. This lesson should be broken up into 3 class periods of an hour for each class.
  • Measuring pots: Students will use an activity sheet or modern pottery rim sherds to compute circumference from a section of a circle and construct analogies based on their own experience about possible functions of ancient or historic ceramics.

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Learning outcomes

Students will:

  • discover the relationship between the circumference and diameter of a circle (Pi).
  • use that discovery to determine the circumference of any circle with a given diameter or radius.

Teacher planning

Time required for lesson

60 Minutes


  • Rulers
  • String for measuring
  • Collection of circular objects of various sizes (such as plastic lids)
  • Chart for data collection
  • Assessment worksheet
  • Calculators


  • A few days prior to this lesson ask students to help begin a collection of various circular objects. Show a few appropriate examples of the kinds of things needed. Strive for variety of diameters. You will need enough for each group of 3 or 4 students to have a variety with which to work.
  • Number each of the circular objects you will be using.
  • Review the terms diameter and circumference.


  1. Divide the class into small groups of 3 or 4.
  2. Give each group a collection of the circular objects collected by the class.
  3. Each group should also have rulers, string for measuring, and a chart for collecting their data.
  4. Explain that in this lesson students will be measuring the circumferences and diameters of circles of different sizes and recording those measurements on the chart they have been given.
  5. Discuss the need for the string each group has been given.
  6. Students collect and record their data on the chart provided.
  7. They are to discuss the relationships they observe and answer the questions on the page with the chart.
  8. Small groups share their findings with the entire class.
  9. Students will have discovered that the circumference is a little more than 3 times the diameter.
  10. Introduce the concept of Pi, the symbol, and the number itself.
  11. Using the Math Explorer calculator Pi key, discuss the decimal and how most often it is rounded off as in 3.14. (This may be a good place for a quick review of rounding decimals.)
  12. Discuss how they have the necessary information to arrive at the circumference of any circle if the diameter or radius is given.
  13. Return to small groups, exchange circular objects, and measure diameters.
  14. Estimate and then calculate circumferences using a calculator or pencil.
  15. Discuss findings in large group.
  16. Complete the assessment worksheet.


  • Observation of small group activities
  • Data Collection Charts
  • Large group discussion
  • Assessment worksheet

Supplemental information


Students who often have difficulty with math will almost always remember this concept after doing this activity.

  • Common Core State Standards
    • Mathematics (2010)
      • Grade 6

        • The Number System
          • 6.NS.3Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation.
        • Grade 8

          • 8.NS.1Know that numbers that are not rational are called irrational. Understand informally that every number has a decimal expansion; for rational numbers show that the decimal expansion repeats eventually, and convert a decimal expansion which repeats eventually...

North Carolina curriculum alignment

Mathematics (2004)

Grade 6

  • Goal 1: Number and Operations - The learner will understand and compute with rational numbers.
    • Objective 1.03: Compare and order rational numbers.
    • Objective 1.04: Develop fluency in addition, subtraction, multiplication, and division of non-negative rational numbers.
      • Analyze computational strategies.
      • Describe the effect of operations on size.
      • Estimate the results of computations.
      • Judge the reasonableness of solutions.