Dimensions of a Circle

Derive the formulae for the circumference and area of a circle using multiple representations.

Publisher: Texas Instruments UK

Editor: Barrie Galpin

Author: Allan Duncan

Topic:  Mathematik

Tags  Umfang ,  Fläche ,  Kreise ,  Geometrie

The tns file allows students to change the size of a circle and "capture" the length of its radius, diameter, circumference and area.

These data are stored automatically in a spreadsheet (page 1.4) and graphs can be drawn and analysed using pages 1.5 to 1.7. The dimensions of the circle are therefore represented in three ways: using geometry, as data in a spreadsheet, and in graphical format.

A lesson using this activity is described by Allan Duncan in a booklet entitled Inspired Connections in Maths Lessons. This description makes clear the power of the dynamically linked multiple representations to enhance student understanding.For a pdf version of the entire booklet please click here.


a) On page 1.4, to clear the data collected, use

<3>< 4>

b) To redraw the graphs with axes appropriate for the data use the Zoom - Data command:

<5>< 2>

Publisher specific license