Geogebra/C3/Relationship-between-Geometric-Figures/English

Title of script: Relationship between Geometric Figures

Author: Madhuri Ganapathi

Keywords: Cyclic quadrilateral, Incircle, Compass, Segment between two points, Circle with center through point, Polygon, Perpendicular bisector, Angle bisector, Angle "Regular Polygon , Move, video tutorial.

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Visual Cue	Narration
Slide Number 1	Hello everybody. Welcome to the Geogebra tutorial on Relationship between different Geometric Figures in Geogebra We assume that you have the basic working knowledge of Geogebra. If not, please go through the “Introduction to Geogebra” tutorial before proceeding further.
Slide Number 2	Please note that the intention to teach this tutorial is not to replace the actual compass box. Construction in GeoGebra is done with the view to understand the properties.
Slide Number 3 Learning objectives	In this tutorial we will learn to construct Cyclic quadrilateral In-circle
Slide Number 4 System Requirement	To record this tutorial I am using Linux operating system Ubuntu Version 10.04 LTS Geogebra Version 3.2.40.0
Slide Number 5 GeoGebra Tools used in this tutorial	We will use the following tools of Geogebra for the construction compass segment between two points circle with center through point polygon perpendicular bisector angle bisector angle
Switch to Geogebra window Applications>>Education>>Geogebra	Let us open the Geogebra window. Let us now construct a cyclic quadrilateral.
Click regular polygon tool >> default value 4 >> click OK >> construct square	Using the “regular polygon” tool click on any two points on the drawing pad. A dialog box will open with a default value '4'. click on OK. A square 'ABCD' is constructed
Click move tool>> tilt to angle angle	Using “move” tool tilt the square to 45^0(degree) angle. To do this place, the mouse pointer on 'A' or 'B'
Click perpendicular bisector tool>>click point 'A' and 'B'	To construct a perpendicular bisector on segment 'AB' Select “perpendicular bisector” tool, click on point 'A' and then on 'B'
Click perpendicular bisector tool>>click segment 'BC'	To construct the perpendicular bisector on 'BC', we will follow the same process. Select “perpendicular bisector” tool, click on point 'B' and then on 'C'
Point to the intersection point>> mark point as 'E'	The two perpendicular bisectors intersect at a point . Let us mark it as 'E'
Click compass tool>> construct circle	Using the “compass” tool, draw a circle with centre as 'E' which passes through C . The circle will pass through all the vertices of the quadrilateral Did you know , the cyclic quadrilateral has maximal area among all quadrilaterals having the same sequence of side lengths
Click on file>>Click on "Save As" >> type "cyclic_quadrilateral" in file name >> click on OK.	Lets save this file now. Click on file then on "Save As". I will type the file name as "cyclic_quadrilateral" and click on save
Click File>> New window	Let us now construct an incircle. I will open a new geogebra window
Click polygon tool>> draw triangle	Using the “polygon” tool click three points on the drawing pad and draw a triangle 'ABC'
Click angle tool >> measure the angles	Select the “angle” tool and measure the angles 'BAC' , 'CBA' and 'ACB'. click the points in the same direction.
Draw angle bisectors >> to angles 'BAC' and 'CBA	Lets draw angle bisectors to angles 'BAC' and 'CBA' using “angle bisector” tool
Hover the mouse on Point of intersection	The two angle bisectors intersect at point . Mark this point as 'D' .
click "perpendicular line” tool>>draw perpendicular line	Using “perpendicular line” tool draw a perpendicular line through 'AB' which passes through 'D'
Lines meet at 'E'	The perpendicular line intersects 'AB' . Mark it as 'E'
Compass tool>>draw circle	Using the “compass” tool let us draw a circle with radius 'DE' . An in-circle is drawn. With this we come to an end of this tutorial
Slide number 6 summary	In this tutorial we have learnt to draw cyclic quadrilateral and In-circle
Slide Number 7 Assignment	Draw triangle ABC M a point D on BC and join AD Draw in-circles for each triangles ABC, ABD and CBD of radii r, r1 and r2 resp. BE is the height h verify the relationship between r1,r2 and r as (1 -2r1/h)*(1 - 2r2/h) = (1 -2r/h) by moving the vertices of the Triangle ABC
Show the output of the Assignment	The output should look like this.
Slide number 8 Acknowledgement	Watch the video available at http://spoken-tutorial.org /What is a Spoken Tutorial It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it
	The Spoken Tutorial Project Team : Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, contact sptutemail@gmail.com
	Spoken Tutorial Project is a part of the Talk to a Teacher project It is supported by the National Mission on Education through ICT, MHRD, Government of India More information on this Mission is available at http://spoken-tutorial.org /NMEICT-Intro
Slide Number 9 About the Contributor	This is Madhuri Ganapathi from IIT Bombay signing off

Contributors and Content Editors

Chandrika, Madhurig, Nancyvarkey