Education Technology

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  • Subject Area

    • Math: Geometry: Circles
    • Math: Statistics: Inferential Statistics

  • Author

    Texas Instruments

  • Level


  • Activity Time

    60 Minutes

  • Device
    • TI-30X IIB
    • TI-30X IIS
    • TI-34 II Explorer Plus™
  • Other Materials
      This is Activity 15 from the EXPLORATIONS Book:
      Math Investigations with the TI-30X IIS: Activities for Secondary Mathematics

      The following materials are needed for this activity:
    • String
    • Ruler
    • Graph paper
    • Spaghetti
    • Glue
    • Several round objects of various sizes
    • Cardboard paper towel tube and an oatmeal box
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Looking at Statistics Through Circles

Activity Overview

Students will measure round objects to determine the circumference and diameter, and use the data to explore geometric concepts of the circle with statistics.

Before the Activity

  • See the attached PDF file for detailed instructions for this activity
  • Print pages 148 - 149 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to the class.

    Follow the activity procedures:

  • Measure the diameter and circumference for each round item and record the values in a table
  • Explore the relationship between the circumference and diameter
  • Observe that the ratio of circumference to the diameter is the same for all round items
  • Plot the circumference versus diameter data
  • Draw a best-fit line and determine its slope
  • Measure the diameter of the cardboard paper towel tube
  • Use the graph to estimate the tube's circumference
  • Use the calculator to find an equation for the line
  • Use this equation to predict the circumference of the tube
  • Measure the circumference of the tube and compare it with the prediction and the estimate
  • Similarly, determine the measure of the diameter of the oatmeal box
  • After the Activity

    Students complete the Student Activity pages.

  • Review student results
  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary