Geometry Explorer Help

Using the Measure Menu: Using Tables

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Tables of measurments are useful for analyzing relationships between different properties of an object. For example, suppose we want to analyze the properties of the interior angles of a Euclidean quadrilateral. First, we construct a quadrilateral in a Euclidean canvas.

table1

Next, we measure the four interior angles. Select the points of the quad in gorups of three and select Angle from the Measure menu for each group of three. (Be careful that you select the points in the right order for interior angles)

table2

Now, we create a compound measure that reflects the sum of the four interior angles. Using the Calculator, sum up the four angles and add this new result to the canvas.  (Go here to review how to use the Calculator)

table3

The sum of the angles appears to be 360. We will create a tabel to hold all of these measurements to record evidence for this result.  Select the four angle measurements and the new  compound measurement and choose "Create Table" under the Measure menu.

table4

Note that the long expression for the sum of the angles has been truncated. If expressions are longer than twenty characters they will be truncated in this fashion.  To add evidence for our sum of angles formula, move the vertices of the quad to another configuration, select the table, and click "Add to Table" under the Measure menu. A new column of data will be added to the table.

table5

The sum of the angles is still 360.  We could addinmg columns to our table to get more and more data for our conjecture.  Now, suppose we did not like the last truncated label in the table. To edit the table, we select the table and choose "Edit Table..." under the Measure menu.  The dialog box below will appear.  To change an entry we just click on that entry in the list and type in a new label.  In this case, we change the name to "Sum of Angles." Once we click OKAY, the new label will appear in our table.

table edit panel