# Geogebra/C2/Symmetrical-Transformation-in-Geogebra/English-timed

From Script | Spoken-Tutorial

Time | Narration |
---|---|

0:00 | Hello everybody.Welcome to this tutorial on Symmetrical Transformation in Geogebra |

0:06 | In this tutorial we will learn Symmetrical transformations such as |

0:11 | Line symmetry |

0:12 | Rotation symmetry |

0:13 | and also learn to
Enlarge figure with scale and position |

0:17 | We assume that you have the basic working knowledge of Geogebra |

0:21 | If not, For relevant tutorials, Please visit our website |

0:26 | To record this tutorial I am using
Ubuntu Linux OS Version 11.10 |

0:31 | Geogebra Version 3.2.47.0 |

0:35 | We will use the following Geogebra tools |

0:37 | Reflect Object about Line |

0:39 | Rotate Object around Point by Angle |

0:42 | Dilate object from a Point by Factor |

0:45 | Semicircle through Two points |

0:47 | Regular Polygon and |

0:49 | Perpendicular bisector |

0:51 | Definition of Transformation |

0:53 | Symmetrical transformation of a geometric figure is - |

0:57 | A change in its position, size or shape on a coordinate plane |

1:02 | Original figure is called 'Object' |

1:04 | Transformed figure is called 'Image' |

1:07 | Reflection symmetry |

1:09 | Is also called as Line symmetry |

1:11 | A type of symmetry where one half is the reflection of the other half |

1:15 | You could fold the image and have both halves match exactly |

1:20 | Line of Symmetry is the line over which the figure is reflected. |

1:24 | Let's Switch to GeoGebra window |

1:27 | Look on Dash home >>Media Apps>>Under Type >>Choose Education>> and Geogebra |

1:37 | For this tutorial I am closing the Algebric view |

1:40 | Click on Close button on Algebric view |

1:47 | Let's start with “Line of symmetry” |

1:50 | First let's construct an equilateral triangle. |

1:53 | Select “Regular Polygon” tool from the toolbar. |

1:57 | Click on drawing pad points 'A' ,'B', and enter 3 for the number of sides. |

2:08 | An equilateral triangle 'ABC' is drawn |

2:11 | Let's draw a perpendicular bisector to one of the sides of triangle |

2:15 | Select “Perpendicular Bisector Tool” and click on side AC |

2:26 | Select the Point tool and create a point inside the triangle. |

2:31 | Move the point D towards one of the vertices . |

2:38 | Right click on point D and select Trace ON |

2:43 | Select “Reflect Object about Line”tool from the tool bar |

2:48 | Click on the point D |

2:49 | This will highlight Point D |

2:52 | Click on perpendicular Bisector |

2:55 | This will produce reflected image D' on the other side of perpendicular bisector |

3:01 | 'D is mirror image of point 'D' |

3:04 | Set Trace On for the point D' |

3:08 | Let us move the point D along the triangle using Move tool |

3:11 | Click on the first option under Move tool from the toolbar |

3:22 | Click on figure with the mouse. |

3:25 | Drag it tracing the triangle . |

3:28 | Now release the mouse button. |

3:31 | What do you notice ? |

3:32 | Here perpendicular bisector is the line of symmetry |

3:36 | D is the object and D' is the image |

3:39 | Let's reflect a semicircle about a line |

3:43 | Let's draw a semicircle |

3:44 | Click on the “Semicircle through Two points” tool Mark point E and then F |

3:56 | Click on segment Between two Points |

4:02 | Mark points G and H A line is drawn |

4:06 | Let's change the property of the line |

4:08 | Right click on the line Object properties Click on Style change Style |

4:21 | Select “Reflect Object about Line” tool from the toolbar |

4:27 | Click on the semicircle EF |

4:31 | Click on line GH |

4:34 | This will produce the reflected image E'F' on the other side of line GH What does the figure look like now ? It looks like a circle |

4:45 | Let us save this file now |

4:47 | Click on “File”>> "Save As" |

4:50 | I will type the file name as "Line-symmetry" and click on “Save” |

5:05 | Next, let us learn to “Rotate the Object around a Point by Angle” |

5:12 | Definition of Rotation |

5:15 | A rotation is a transformation that turns a figure around a fixed center by an angle |

5:21 | If the figure appears unchanged, then the figure has rotation symmetry |

5:29 | You can rotate object at any degree measure Rotation can be clockwise and counterclockwise |

5:39 | Let's open a new Geogebra window |

5:41 | click on “File” >> New |

5:47 | Let us construct a square. |

5:49 | click on “Regular Polygon” tool from the toolbar |

5:55 | Click on the drawing pad |

5:57 | Mark points 'A' and 'B' |

5:59 | A dialog box opens |

6:01 | Click on OK |

6:03 | A square 'ABCD' is drawn |

6:05 | Click on “Rotate Object around a Point by Angle” tool |

6:13 | Click on the Square 'ABCD' |

6:16 | This will highlight the square |

6:18 | Next Click on any one of the vertices |

6:20 | I will click on 'A' |

6:23 | A dialog box opens |

6:25 | Type “60” in the Angle field |

6:30 | Select "°" from first drop down list |

6:35 | Select the option “clockwise”
Click on OK |

6:40 | This will rotate the square clockwise at the point of selection with the angle of 60° |

6:44 | The rotated image 'A`B`C` 'D' is formed |

6:49 | Let's move this figure aside using Move tool |

7:00 | Next, let's “Dilate or enlarge object from point by factor” |

7:09 | Dilation |

7:11 | Dilation or enlargement is a transformation |

7:14 | in which a figure is enlarged using a scale factor |

7:23 | Let's draw a triangle Using the “Polygon”tool |

7:28 | E , F , G click on E again to complete the triangle |

7:36 | Click on New point tool and |

7:40 | Mark a point 'H' |

7:44 | Click on “Dilate Object from Point by Factor” tool |

7:51 | Click on the triangle 'EFG' |

7:54 | This will highlight the triangle |

7:55 | Click on the point 'H' |

7:57 | A dialog box opens |

8:00 | Type value of 2 in the number field |

8:04 | Click on OK |

8:09 | This will dilate or enlarge the object twice |

8:16 | Click on Segment Between two Points, join points H,E,E' |

8:33 | join points H,G,G' |

9:01 | join points H,F,F' |

9:15 | Here you can see that H is the point of dilation |

9:21 | You can enlarge object as number of times as you wish, by typing the value of Factor |

9:28 | Let us save this file now |

9:30 | Click on “File”>> "Save As" |

9:33 | I will type the file name as "Dilate-triangle" |

9:48 | Click on “Save” with this we come to the end of this tutorial |

9:55 | Let's summarize |

9:58 | In this tutorial we learnt |

10:00 | Reflection about a line |

10:02 | Rotation of an object at a point |

10:05 | Enlargement of an object by a scale factor |

10:09 | As an assignment I would like you to |

10:11 | Draw a Pentagon |

10:12 | Use Regular Polygon tool to draw(Hint:sides=5) |

10:17 | Draw a Perpendicular bisector to one of the sides of the pentagon |

10:21 | Create a point in side the pentagon |

10:25 | Set trace On for the point |

10:27 | Get reflection of the point about the perpendicular bisector |

10:31 | Set trace On for the image point |

10:34 | Trace the pentagon to see if you have selected the correct line of symmetry |

10:44 | Rotate the original pentagon counter clockwise in 135° at a point |

10:49 | Dilate the pentagon at a point by the factor of 3 |

10:56 | The assignment should look like this |

11:03 | Watch the video available at this URL |

11:06 | It summarises the Spoken Tutorial project |

11:09 | If you do not have good bandwidth,you can download and watch it |

11:12 | The Spoken Tutorial Project Team :
Conducts workshops using the spoken tutorials |

11:17 | Gives certificates to those who pass an online test |

11:20 | For more details, please write to
contact@spoken-tutorial.org |

11:26 | Spoken Tutorial Project is a part of the Talk to a Teacher project |

11:29 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |

11:35 | More information on this Mission is available at this link. |

11:39 | This is Neeta Sawant from SNDT University Mumbai signing off.
Thanks for joining |

## Contributors and Content Editors

Madhurig, Minal, Mousumi, PoojaMoolya, Pratik kamble, Sandhya.np14