Texas Instruments TINSPIRECX Multiple Representations, Draw and Measure a Circle, Measured circle

First Steps with TI-Nspire™

Appendix: Multiple Representations

Appendix

Multiple Representations

The previous seven tutorials have introduced many of the key features of TI-Nspire learning technology, with each of the applications being discussed separately. However, one of the great strengths of TI-Nspire is that it allows the applications to be linked dynamically, encouraging different approaches to problem solving. This appendix offers an example of what is meant by “multiple representations”, showing how several of the applications can be used to investigate a mathematical concept, in this case the relationship between a circle’s diameter and circumference and between its radius and area.

By working through this appendix you will be able to revise many of the skills and techniques you met in the tutorials. Here detailed instructions and key presses have been omitted though you will find back references if you need to remind yourself about particular techniques. However, try to concentrate on the big picture of what is going on, asking yourself how each of the multiple representations contributes to a deeper understanding of the mathematics.

Draw and Measure a Circle

•Open a new document with a Geometry page.

•Construct a large circle on the screen.

•Construct a radius by drawing a segment from the centre to the circumference.

•To construct a diameter first construct a line (not a segment) from the centre to the circumference. Then construct the Intersection Points of the line and the circle: this generates the point on the opposite end of the diameter.

•Now measure the lengths of the radius, the diameter and the circumference. Also measure the area. In each case change the number of decimal points displayed.

• Finally assign the measurements to variables. Click on
	A measured circle
each measurement in turn. Press h. Type the letter
appropriate for each measurement (r, d, C and A) and
press ·.
• Check that the measurements all change when you
grab the edge of the circle and change its size.

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