Geometric representation of the sum of two radicals

This activity is part of the lesson on adding radicals posted at Mathematics for Teaching.

How to construct the figure:

Use the regular polygon tool. Click on two points (endpoints of the diagonal of 2 by 1 unit square in the grid). From then on just click on the diagonals each time to generate the squares.

To type the radical, use the text tool, click anywhere on the grid, check latex in the dialogue window and type \sqrt{5} and you're done.

To change the color, right click on the figure, click color, choose and you're done.

When you are ready click on the file menu and choose new. This will give you a brand new grid to practice constructing the figure.





















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Constructing regular polygons

This is an introductory task for teaching squares and square roots. Click here to view the full sequence of the lesson.

Activity

The pentagon was constructed by clicking the regular polygon tool and then clicking on the grid twice. In the dialogue window, type the number 5 for the number of sides. In the dialogue window you will see information about the polygon.

Your task:
Construct a few more regular polygons using the tool.
Why is it that GeoGebra only needed to know two points and the number of sides to contruct the polygon?






















Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)