Drawings

The GeoGebra window

Image

In the picture above, the the algebra and graphcis view are shown. This is the topmost "perspective" in the perspectives menu. To start with, only these two views are needed,

Each icon in the toolbar will show a drop down list of tools if you click on the small arrow in the lower right corner of the icon.

Image

Each tool will let you enter an object in the graphics view, the toolbar help describes what is needed to make the object. If the toolbar help gives the hint to "select a point", you can either select an existing point by clicking on it, or click anywhere in the graphics view to make a new point. Some objects require other existing objects; as an example, you can not make a parallel line if you don't already have a line in the graphics view.

Image

As long as a tool is selected in the toolbar, clicking in the graphics view will make a new object. Select the Move-tool Icon width=20 height=20> to move an object (it takes a while for beginners to get used to this).

Use the Move-tool to move an object!

Properties

All objects have properties that you can change. The most common properties can be changed by using the styling bar. If no object is selected, the styling bar will show common properties for the graphics view. You toggle the styling bar by using the styling bar icon in the upper left corner of the graphics view.

Image

If you want to change the details of the coordinate system, click on the small wheel in the upper right corner and choose "Graphics". In the window that pops up, you find all the properties of the graphics view.

Image

When an object is selected, the styling bar for that object will be shown. In order to change the styles of the points defining a circle, you must first select a point. Note that the opacity of circles are set to 0 by default, i.e. they are transparent. You can change the opacity in the styling bar.

Image

If you want to see all properties of an object, start by selecting it, then right-click and choose Object Properties; the Object Properties window will pop up.

Names and labels

Each object in GeoGebra is given a name (you can name it yourself or change the given name but not now...). The names of all objects are shown in the algebra view. Some objects are displayed with a label showing the name in the graphics view, this is the case for points. You can hide/show the label of an object by right-clicking on it and then uncheck/check Show Label. You can also use the styling bar to hide or show labels.

Image

You can change the way labels are shown when new objects are created by choosing Options->Labelling in the menu.

Image

Selecting many objects

To select many objects in the graphics view, first choose the Move-tool then press the mouse-button and drag. The selected objects can be moved by using the arrow keys.

Image

You can select several objects in the Algebra view by holding down the shift key. If you want to select all points, press the minus-sign to fold all points, then click on "Point".

Image

There are also other ways to select many and change their properties. Some examples are shown in the recording below.

Views

There are two views shown by default when you start GeoGebra, the algebra view and the graphics view. In the upper right corner of each view there are icons to show the view in a new window or to close the view.

Image

You can find all views under the menu Views.

One of the views is a virtual Keyboard. The Virtual Keyboard is used when using an Interactive Whiteboard. Usually the keyboards displayed by Interactive Whiteboard software are not well-suited for doing mathematics since they lack some of the most common mathematical keys.

Image


Exercise - Make a drawing

Make a self-portrait!

Image

Try the Icon Undo-tool in the upper right corner, Ctrl+z or Cmd+z also works.

Try to zoom in and out using the mouse-wheel or trackpad.

Try to move the drawing (find the tool!)

When you are done you should know how to:

  • Insert/Delete/Move an object.
  • Change the appearance of the graphics view.
  • Change the colour and size of an object.
  • Change the appearance of a polygon and circle.
  • Hide and show labels and objects.
  • Hide and show the views.
  • Insert text including Greek letters. (Don't change the language to Greek unless you really know Greek)
  • Select several objects

Image

If you want to make a symmetric portrait; make half of the face, choose the tool "Reflect object in Line", select all objects and then click on the y-axis.

by Malin Christersson under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 Sweden License

www.malinc.se