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

Published on 06/09/2008

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