Geogebra/C2/Understanding-Quadrilaterals-Properties/English-timed
| Time | Narration |
| 00:00 | Hello everybody. |
| 00:02 | Welcome to this tutorial on Understanding Quadrilaterals Properties in Geogebra. |
| 00:08 | Please note that the intention of this tutorial is not to replace the actual compass box. |
| 00:14 | Construction in Geogebra is done with a view to understand the properties. |
| 00:19 | We assume that you have the basic working knowledge of Geogebra. |
| 00:24 | If not, please visit the spoken tutorial website for the relevant tutorials on Geogebra. |
| 00:30 | In this tutorial, we will learn to construct quadrilaterals, simple quadrilateral and
quadrilateral with diagonals. And also learn their properties. |
| 00:42 | To record this tutorial I am using: |
| 00:45 | Linux operating system Ubuntu Version 11.10, Geogebra Version 3.2.47. |
| 00:55 | We will use the following Geogebra tools for construction of: |
| 01:00 | * Circle with center through point
|
| 01:10 | Let's switch on to the new Geogebra window. |
| 01:13 | To do this, click on Dash home, Media Applications. |
| 01:17 | Under Type, Education and Geogebra. |
| 01:25 | Let us now construct a circle with center A and which passes through point B. |
| 01:30 | To do this, click on the Circle with Center through Point tool from the toolbar. |
| 01:35 | Click on the drawing pad. Point A as center. |
| 01:38 | And then click again, we get point B. The circle is complete. |
| 01:44 | Let us construct another circle with center C which passes through D. |
| 01:49 | Click on the drawing pad. It shows point C. |
| 01:53 | Then click again we get point D. The two circles intersect at two points. |
| 02:00 | Click on the Intersect Two Objects tool below the New Point.
Click on the points of intersection as E and F. |
| 02:10 | Next, click Polygon tool. |
| 02:16 | Click on the points 'A', 'E', 'C', 'F' and 'A' once again.
Here a quadrilateral is drawn. |
| 02:32 | We can see from the Algebra View that 2 pairs of adjacent sides are equal. |
| 02:38 | Do you know why? Can you figure out the name of this quadrilateral? |
| 02:43 | Let us now save the file. Click on File>> Save As. |
| 02:48 | I will type the file name as simple-quadrilateral, click on Save. |
| 03:04 | Let us now construct a Quadrilateral with diagonals. |
| 03:08 | Let's open a new Geogebra window,
click on File >> New. |
| 03:16 | Select the Segment between Two Points tool from the toolbar to draw a segment. |
| 03:23 | Click on the drawing pad, point 'A' and then on 'B'.
Segment AB is drawn. |
| 03:30 | Let's construct a circle with center A and which passes through point B. |
| 03:36 | To do this, click on the Circle with Centre through Point tool. |
| 03:40 | Click on the point A as centre and then on point B.
Select the New Point tool, from the toolbar. click on the circumference as point c. |
| 03:57 | Let us join 'A' and 'C'.
Select the Segment between Two Points tool |
| 04:03 | Click on the points A and C.
Let's now construct a parallel line to segment AB which passes through point C. |
| 04:13 | To do this select the Parallel Line tool from the toolbar.
Click on the point C and then on segment AB. |
| 04:25 | We repeat the process for the point B.
Click on the point B and then on segment AC. |
| 04:33 | Notice that the parallel line to segment AB
and parallel line to segment AC intersect at a point. Let's mark the point of intersection as 'D'. |
| 04:47 | Next using the “Segment between Two Points” tool,
let's connect the points 'A' 'D', 'B' 'C' |
| 05:01 | We see that a Quadrilateral ABCD with diagonals AD and BC is drawn. |
| 05:09 | The diagonals intersect at a point.
Let us mark the point of intersection as E. |
| 05:20 | Using the “Distance” tool,
let's check whether the diagonals bisect each other |
| 05:25 | Under the “Angle” tool, click on the Distance or Length tool. |
| 05:30 | Click on the points A, E, E, D, C, E, E, B |
| 05:47 | Next, we will check whether the diagonals are perpendicular bisectors. |
| 05:51 | To measure the angle, click on the Angle tool.
Click on the points A,E,C C,E,D. |
| 06:08 | Let us now select the Move tool from the toolbar.
Use the Move tool to move the point A. |
| 06:16 | Click on the 'Move' tool,
place the mouse pointer on 'A' and drag it with the mouse. Notice that the diagonals always bisect each other and are perpendicular bisectors. |
| 06:35 | Let us save the file now.
Click on File>> Save As. I will type the filename as quadrilateral, click on Save. |
| 06:53 | With this we come to the end of this tutorial.
Let us summarize. |
| 07:01 | In this tutorial, we have learnt to construct quadrilaterals using the tools - |
| 07:06 | 'Circle with centre through point', 'Polygon', 'Angle',
'Parallel line', 'Segment between two points' and 'Insert Text' |
| 07:15 | We also learnt the properties of
|
| 07:21 | As an assignment, I would like you to: Draw a line segment AB,
mark a point C above the line. Draw a parallel line to AB at C. |
| 07:33 | Draw two points D and E on the parallel Line, join points AD and EB. |
| 07:43 | Draw perpendicular lines to segment AB from D and E.
Mark the points F and G of the perpendicular lines on AB. Measure distance DE and height DF. |
| 08:01 | The output of the assignment should look like this. |
| 08:08 | Watch the video available at this url. |
| 08:11 | It summarizes the Spoken Tutorial project.
If you do not have good bandwidth, you can download and watch it. |
| 08:18 | The Spoken Tutorial Project Team :
Conducts workshops using spoken tutorials Gives certificates to those who pass an online test. |
| 08:27 | For more details, please write to contact@spoken-tutorial.org. |
| 08:34 | The Spoken Tutorial Project is a part of the Talk to a Teacher project.
It is supported by National Mission on Education through ICT, MHRD, Government of India. More information on this Mission is available at this link:
|
| 08:49 | This is Madhuri Ganapathi from IIT Bombay, signing off.
Thanks for joining.
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