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Move, Point and Line Tools

Tools Always remember that the way you get different things to happen is by selecting the appropriate tool from the toolbar (the set of squares with little icons across the top of the window).  Related tools can be found in drop-down menus that appear when you hover over a given box.  Move Tool When a tool is "selected" it will be surrounded with a little blue box. For example, the MOVE tool is selected when the box with the little arrow is highlighted in blue, so your mouse will let you drag or select objects.  You always want to be aware of which tool you are actively using.
Points and Lines There are two basic ways to make points.  The first is by selecting the POINT tool (highlighted in the screen shot) and then clicking somewhere on the graphics panel.  The second is by going to the input box in the left column, typing in the point, and hitting enter.
Instructions for Task: Step 1. a. Create a point "A" with the POINT tool and then, b. In the INPUT panel box, type in another point "B" by typing the syntax B = ( x-coord,y-coord).  Activate the MOVE tool and then move both points around to see how that works. Next to the POINT tool is the LINE tool.  You can use it to either create a line through two existing points (by clicking on the existing points) or to create two new points with a line through them (by clicking on any locations in the graphics window that do not already contain points). Step 2. Use the LINE tool to: a. Create a line through AB (the points you already created in Step 2) and then, b. Use it to create a line through two new points (call the two points CD). Step 3. Now select the MOVE tool and put points C and D at (-1, 1) and (1, 3).  Step 4. Use algebra techniques to find an equation for line CD, then write down the equation that GeoGebra gives for this line.  Finally, show on paper that these two equations describe the same line. Enter the equation you got in the response section below.


What is the equation of line CD?