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

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