Hello Everybody. Welcome to the tutorial Introduction to Geogebra. In this tutorial, I will introduce you to the basics of getting started with Geogebra.
What is Geogebra ? It is a free mathematics software and is available at www.geogebra.org to download.
It is useful for computer aided learning as it is interactive and you can see the algebraic expressions of geometric figures and vice versa.
It combines geometry , algebra and calculus. So you can construct geometric figures, enter equations, deal with variables, vectors etc..
To get started with Geogebra, I am using the Linux operating system Ubuntu Version 10.04 LTS and Geogebra Version 3.2.40.0.
If you have already installed Geogebra, go to the Ubuntu Menu item Applications,Education or Science and click on the Geogebra Application.
If you have not installed Geogebra, please go to System , Administration, Synaptic Package Manager to install Geogebra.
Now let us explore the Geogebra window. In this tutorial I will briefly explain the menu bar, the tool bar and tool view, the graphics view and algebra view,the input bar and commands.
A typical Geogebra window looks like this. It has a standard menu bar like any window based application.
The tool bar is like the compass box of Geogebra.
The tool view tells you which tool is selected and ready for use.
The graphic view is the drawing pad of Geogebra. You can construct geometric figures on this pad.
This is the algebra view. In this window you can see the algebraic expressions of all the geometric figures constructed on the drawing pad.
The Input Bar allows you to input algebra equations which will be made visible on the drawing pad as well as the algebra view.
The commands supported by Geogebra in the Input Bar are in this drop down menu.
The drawing pad is always visible in Geogebra and cannot be closed.
On the drawing pad, you can use the grid by going to View and checking on the Grid option.
Similarly you can un-check the Axes if you don't want to see it. We will keep the Axes and Grid visible for this tutorial.
If you choose to close the algebra view or Input Bar you may do so by going to View and un-checking the option. Let us remove the Input Bar from this tutorial.
Now the tool bar, a compass box in more detail. To use a tool, click on an item.
Notice when you click on it, a dark blue border appears around the item, indicating that it is selected and it's name and a hint on how to use it also appears in the tool view.
The Move Drawing Pad is the right most tool item. Click on it and then click on the drawing pad. Keep the left click depressed and move the drawing pad to the desired position.
If we start with the pencil in the compass box, in geometry we can draw a point with a pencil.
The pencil tools are here. If you click on the small red triangle in the corner of the tool you will see all the pencil or the point tools.
Similarly the next set of tool items are for lines. Then these Perpendicular lines and Bisectors, Polygons, circles etc.
In this tutorial, I am going to take you through drawing points, line segments, parallel and perpendicular lines, measuring objects , changing object properties and saving a file.
Now let us draw points. Select the New point option, click on anywhere on the drawing pad. You get new points.
Notice that the point appears on the drawing pad as well as in the algebra view.
All tool items drawn on the drawing pad are called objects in Geogebra.
Points A and B are Free Objects, that is they are not dependent on any other object on the drawing pad.
You can draw a line segment by going to Segment between Two Points, using two existing points like A and B or click anywhere else on the drawing pad and you will get two new points and the segment between these two points.
Similarly, you can draw a perpendicular line by checking a point and then the line. You will get a perpendicular line through point D, perpendicular to segment CD.
A parallel line, I will click on a point anywhere here and select AB. I get a parallel line to AB through point E.
Now you can find the point of intersection of two objects if you go to this tool here and click on Intersect two objects.
When you move your mouse over the intersection, both the objects get highlighted. At that time click, you will get the intersection of the two objects.
To measure the distance, click on the fourth from right tool bar and select Distance or length tool.
You may measure the distance between points by selecting the two points, clicking DF here, or you may select an entire line segment.
Notice that there are no unit on the grid. We will explore unit names in more advanced topics.
You can change the properties such as the label and colour of each of the items. Before that
if you don't want to draw any object, please use the arrow key here. So, if you use that it will not draw any object on the drawing pad.
Now, to change the object properties move your mouse over the object. When it gets highlighted right click and click on Object Properties.
Here I will take you through some of the basic properties, more details in another advanced topic.
To change the Name, type a new name. You can also type a caption. You can choose to show the object or not show it.
You can choose to not show the label or you can show one of these options. Let's keep the caption on.
In the colour tab you can change the colour of the line.
In the style tab you can change the thickness and you can change the style.
When you close this you have the new appearance of the line.
The left most tool item, the Move tool item, is a very useful tool for teaching as it makes the lesson dynamic and interactive.
All Free Objects may be moved.
All the Dependent Objects of the free objects will move preserving their property, when the Free object is moved.
For example if we move points A or B , you will notice that the parallel line also moves along maintaining its parallel property.
To save a file, select the item File, select Save As . Select the folder. I will go to Documents, Geogebra. Enter the file name and click Save.
Notice that the name appears in the top panel and it is saved as a .ggb file, like all geogebra files.
Now to open a file you have to click on File, Open and select any file to open.
Finally the ASSIGNMENT.
In the assignment I would like you to draw a rectangle by using the Segment between two points tool, start with that.
Then use the Parallel Line and Perpendicular Line, the Intersect two Objects and the Distance or Length tools.
Finally test the rectangle you have constructed by using the Move tool and move the free objects.
I have already constructed this assignment here. I have started with Line segment AB and I have constructed the rectangle ABED.
Now if I click on the Move tool item and move the Free objects notice that any position my rectangle ABED remains a rectangle if constructed properly.
I would like to acknowledge the spoken tutorial project which is part of the talk to a teacher project.
It is supported by the National Mission on Education through ICT, MHRD government of India.
And you can see more information about this at this website.
Thank you. This is Bindu, signing off. Enjoy exploring Geogebra.