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 Polygon |
00:54 | New point and |
00:56 | Insert text 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 a 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.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.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. |
10:23 | It summarizes 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 |