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 sized 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^2h |
| 10:13 | The output of the assignment should look like this. |
| 10:19 | Watch the video available at this URL |
| 10:23 | It summarises the Spoken Tutorial project |
| 10:26 | If you do not have good bandwidth, you can download and watch it |
| 10:31 | The Spoken Tutorial Project Team : |
| 10:33 | Conducts workshops using spoken tutorials |
| 10:36 | Gives certificates to those who pass an online test |
| 10:40 | For more details, please write to
contact@spoken-tutorial.org |
| 10:48 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 10:52 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
| 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 |
