Geogebra/C3/Mensuration/English-timed

Time	Narration
00:00	Hello everybody Welcome to this tutorial on Mensuration in Geogebra.
00:06	In this tutorial, we will learn to find:
00:09	* Area and perimeter of rhombus
00:12	* Surface area of sphere and cone
00:15	* Volume of sphere and cone.
00:20	We assume that you have the basic working knowledge of Geogebra.
00:24	For relevant tutorials on Geogebra,
00:27	please visit our website.
00:31	To record this tutorial, I am using:
00:33	Ubuntu Linux OS Version 11.10
00:38	Geogebra Version 3.2.47.0
00:42	We will use the following Geogebra tools:
00:46	* Segment between two points
00:48	* Circle with center and radius
00:51	* Ellipse
00:52	* Polygon
00:54	* New point and
00:56	* Insert text
00:57	Let's open a new Geogebra window.
01:00	Click on Dash home and Media Apps. Under Type, choose Education and Geogebra
01:13	Let's find the area of a rhombus.
01:15	Let's use the file quadrilateral.ggb of the previous tutorial.
01:20	Click on File, Open, click on quadrilateral.ggb.
01:27	Click on Open.
01:29	Area of the Rhombus =1/2 * product of diagonals.
01:34	To demonstrate it:
01:36	Click on the Insert Text tool.
01:39	Click on the drawing pad. A text box opens.
01:44	Area of the rhombus =+(1/2 g f) Open the double quotes(“), type: Area of the rhombus = close the double quotes + for concatenation open the brackets, type: 1/2 space f space g close the bracket f and g are the diagonals of the rhombus.
02:09	Click OK.
02:11	Area of rhombus is displayed here on the drawing pad.
02:14	Next, let's find perimeter.
02:17	Click on the Insert text tool.
02:19	Click on the drawing pad. A text box opens.
02:22	Open the double quotes(“) type: Perimeter of the rhombus =+(4 a) close double quotes '+' open the brackets 4 space 'a' close the brackets a is the side of the rhombus.
02:44	Click OK.
02:46	Perimeter of rhombus is displayed here on the drawing pad.
02:50	Let's now save the file.
02:53	Click on File and Save As.
02:55	I will type the filename as rhombus-area-perimeter
03:12	Click on Save.
03:17	As an assignment, I would like you to find area and perimeter of trapezium,
03:22	use output of file cons-trapezium.ggb.
03:27	Rename object g as b.
03:30	Formula for area = (half sum of parallel sides) * (vertical height) = (a+b)/2* h
03:40	Formula for perimeter =(sum of the sides) =(a+b+c+d)
03:49	The output of the assignment should look like this.
03:54	Let's open a new Geogebra window to draw a sphere.
03:58	Click on File , New
04:01	Click on the Circle with center and radius tool from the toolbar.
04:06	Click on the drawing pad point A. A text box opens.
04:11	Enter value 2 for radius.
04:13	Click OK.
04:15	A circle with center A and radius 2cm is drawn.
04:19	Select New point tool from tool bar, mark a point B on the circumference of the circle.
04:26	Select Segment between two points tool.
04:29	Join points A and B as radius of the circle.
04:34	Let's draw an ellipse CDE in the horizontal direction, to touch the circumference of the circle.
04:42	Click on Ellipse tool.
04:45	Mark points C and D diagonally opposite to each other on the circumference and a third point E inside the circle.
04:56	Here a sphere is drawn.
04:59	Let's now find the Surface area of the sphere.
05:03	Click on Insert text tool.
05:05	Click on the drawing pad. A text box opens.
05:08	Please find the special characters in the drop down list in the text box. Scroll down to find π (pi).
05:17	open double quote, type: Surface area of the sphere = +( 4 π a2) close double quote plus open the bracket 4 space select π from the list space a select 'square' from the list close the bracket.
05:45	Click OK
05:47	surface area of the sphere is displayed here.
05:52	Let me click on it and drag it, place it below.
05:56	Next, let's find volume.
05:59	Click on the Insert Text tool.
06:00	Click on the drawing pad, Text box opens.
06:03	open double quote type: Volume of the sphere = +(4/3 π a^3) close double quote plus open the bracket 4/3 space select π from the list space a select cube from the list close the bracket
06:31	click OK.
06:34	Volume of the sphere is displayed here.
06:36	Let me click on it and drag it to place it below.
06:40	Next, let's draw a cone.
06:43	Click on Polygon tool.
06:45	Click on points C , D and an external point F and C once again.
06:53	Select Segments between two points tool join points F and A.
06:59	We get height of the cone.
07:03	Let me rename the object b as h which denotes height of the cone.
07:08	Right click on object b.
07:09	Click on Rename.
07:11	Replace b with h click OK.
07:15	Let me also Rename the object c_1 as s which denotes slant height of cone.
07:21	Right click on object c_1.
07:23	Click on Rename.
07:24	Replace c_1 with s.
07:26	Click OK.
07:28	Let's find now surface area and volume of the cone.
07:33	We can use either the Insert text tool from the tool bar or we can use the Input bar. I will use the Input bar.
07:40	Please find the special characters in the drop down list of the Input bar.
07:44	Scroll down to find π.
07:48	Type in the input bar: Area = (π a s + π a²) Surfacearea = open the bracket Select 'π' from the list space a space s plus select π from the list space a Select square from list close the bracket press Enter.
08:15	Surface Area of the cone is displayed in the Algebra view.
08:20	Please note when we use the Input bar answer appears in the Algebra view.
08:26	Let's find Volume.
08:29	Volume =(1/3 π a² h) Volume =open bracket 1/3 space select 'π' from the list space a Select square from list space h close the bracket Press Enter.
08:50	Volume of the cone is displayed here in the Algebra view.
08:55	Lets now save the file. Click on file Save As. I will type the file name as Sphere-cone.
09:08	Click on Save.
09:10	With this we come to the end of this tutorial.
09:14	Let us summarize.
09:18	In this tutorial we have learnt to find:
09:20	* Area and perimeter of rhombus
09:24	* Surface Area of sphere and cone
09:27	* Volume of sphere and cone.
09:30	We have also learnt to draw sphere and cone.
09:36	As an assignment, I would like you to find Surface area and volume of cylinder.
09:43	Draw 2 ellipses of same size, one below the other.
09:47	Connect edges of ellipses.
09:50	Use Center tool, find center of one ellipse.
09:54	Join center and edge.
09:56	Rename object b as h and e as r.
10:01	Surface area = 2 π r(r + h)
10:07	Volume = π r^2 h
10:13	The output of the assignment should look like this.
10:19	Watch the video available at this URL.
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10:26	If you do not have good bandwidth, you can download and watch it.
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10:48	Spoken Tutorial Project is a part of the Talk to a Teacher project.
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10:59	More information on this mission is available at this link.
11:06	This is Madhuri Ganapathi from IIT Bombay, signing off. Thanks for joining

Contributors and Content Editors

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