2) Demonstrating Free-hand Drawing of an Image using Line Segments, Circle and Arc using GeoGebra

Demonstrating Free-hand Drawing of an Image using Line Segments, Circle and Arc using GeoGebra

Drawing and Colouring the Pictures (Part 2)

You have learnt drawing a house by using 'Polygon' tool in GeoGebra. You have also learnt how to colour it. Now, we are going to draw pictures having circles. You will also learn how to change colours and other attributes of the objects.
Let us start now
Opening a file with geometrical view: To open a new file,
double click on  GeoGebra icon on your desktop.
When you open a new file, it will look like as in Fig. 01.
Immediately after opening GeoGebra, it shows 'GeoGebra Math Apps' box (OR) 'Perspectives' box. The Axes which are appearing will get disappeared. Select 'Geometry' in those options which are shown in the box. The other way to make these axes disappear is go to 'View'  and uncheck 'Graphics'. Then, go to 'View' in the main menu and uncheck 'Algebra'.

                    (Fig. 01)




Now, we are ready to draw another diagram. Let us draw a stick diagram as shown beside.




Drawing a stick diagram:
Go to 'Toolbar'  and select 'Circle'.


                (Fig. 02)
              
Select a location on the screen and click on the screen. A point will appear. Then drag the mouse keeping the mouse button pressed. You will see a circle drawn with size increasing. You can draw a circle with the size you desire as shown in the Fig. 03a and 03b.

            (Fig. 03a)

                (Fig. 03b)
Select a point in the circle to draw eye of the stick diagram and draw a small circle as shown in the Fig. 04.

                    (Fig. 04)
Then, draw another circle as another eye of the stick diagram as shown in the Fig. 05.

                    (Fig. 05)
Now, our diagram is having a face and the eyes and we have to draw it’s mouth to turn into smiley face. To draw smiley, go to 'Toolbar'--->see the options in ‘Circle’. Then it will show you many options regarding circles. Now, click on 'Circular Arc' as shown in the Fig. 06.

(Fig. 06)
Now, click on the centre of the bigger circle and click at another point from where you want to draw arc (as smiley). Hold and Drag the mouse from left to right as shown in the Fig. 07 and 08.
        
         (Fig. 07)                                        (Fig. 08)
      
Face of our stick diagram is ready now. We have to complete the picture by drawing the remaining body of the face. Let us draw it.
Now, go to 'Toolbar'--->see the options in line. Then it will show you many options regarding lines. Then click on 'Segment' as shown in the Fig. 09.

        (Fig. 09)

Then, click on the circle from where you want to draw a line segment. Hold and drag the mouse to draw a line segment as shown in the Fig. 10 and 11.

                   (Fig. 10)


(Fig. 11)
Next, place a point on the line by clicking on the previous line segment and hold and drag, so as to draw another line segment to draw a hand of the stick diagram as shown in the Fig. 12 and 13.

                              (Fig. 12)

                    (Fig. 13)
And thus, you complete the stick diagram by drawing remaining line segments as shown in the Fig. 14.

(Fig. 14)
But, when we look at the Figure, it is not looking good with so many unnecessary dots/points. We have to hide these points. Let us do it.
To hide a point: Select a point which you want to hide----->right click
You will get the options which are shown in the Fig. 15. Then, uncheck 'Show Object' by clicking on it.


              (Fig. 15)
Similarly, you may repeat the process to hide the other points too which you desire.

                              (Fig. 16)

Changing width of the line segment:
When you look at the Figure, the lines are looking very thin. Let us make these lines thicker as per our need.
To make the line segments thicker:
Select the line segment----> a graphical bar will appear below the Toolbar as shown in the Fig. 17. Click on the 'Line' in the bar as shown in the figure and by moving the thickness meter, you can make the line segment thicker.

                     (Fig. 17)
Now the line segment has become thicker as we wanted. It is shown in the Fig. 18.

(Fig. 18)
In the same way, you can turn your desired lines thicker as shown in the Fig. 19.

(Fig. 19)

Colouring the picture:
Now, let us colour the picture.
To colour the picture, click on the circle---->in the graphical bar select colour---->change opacity by moving meter.
Similarly, you can change the size and colour those shapes which you want.

(Fig. 20)
Now finally save the file.
To save the file:
Press Ctrl+S----> enter file name in the 'File Name’ box---->click on 'Save'.