Difference between revisions of "Formation of a triangle"

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Three lines intersect with each other in a plane to form a closed figure. Vertices are formed at the intersecting points and edges that mark the triangle are sides.
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Introducing formation of a shape with least number of lines and the space enclosed by these lines form a geometric shape.The key geometric concepts that are related with this are explained.  
 
 
 
=== Objectives ===
 
=== Objectives ===
 
*Understand formation of triangles
 
*Understand formation of triangles
 
*Recognize elements of triangle
 
*Recognize elements of triangle
 
*Introduce  concepts of exterior angle.
 
*Introduce  concepts of exterior angle.
[[File:Triangle formation.png|thumb|600x600px|'''[https://www.geogebra.org/m/bwsvgqqg#material/z4h42k8z Introduction to a triangle.ggb]''']]
 
 
 
===Estimated Time===
 
===Estimated Time===
 
30 minutes
 
30 minutes
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*Digital : Computer, geogebra application, projector.
 
*Digital : Computer, geogebra application, projector.
 
*Non digital : Worksheet and pencil
 
*Non digital : Worksheet and pencil
*Geogebra files :  '''“[https://www.geogebra.org/m/bwsvgqqg#material/z4h42k8z Introduction to a triangle.ggb]”'''
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*Geogebra files :  '''“[https://www.geogebra.org/m/kenedcfx Introduction to a triangle.ggb]”'''
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{{Geogebra|kenedcfx}}
  
 
===Process (How to do the activity)===
 
===Process (How to do the activity)===
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[[Category:Triangles]]
 
[[Category:Triangles]]
 
[[Category:Class 8]]
 
[[Category:Class 8]]
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[[Category:Classroom activities]]

Latest revision as of 05:59, 10 May 2019

Introducing formation of a shape with least number of lines and the space enclosed by these lines form a geometric shape.The key geometric concepts that are related with this are explained.

Objectives

  • Understand formation of triangles
  • Recognize elements of triangle
  • Introduce concepts of exterior angle.

Estimated Time

30 minutes

Prerequisites/Instructions, prior preparations, if any

Prior knowledge of point, lines, angles, parallel lines

Materials/ Resources needed


Download this geogebra file from this link.


Process (How to do the activity)

  • Use the geogebra file to illustrate. The questions below will are used to interact with the geogebra sketch.
  • How many lines are there? Are the lines meeting?
  • Are the two lines parallel? How can you say they are parallel or not?
  • How many angles are formed at the point of intersection?
  • What is the measure of the total angle at the point of intersection of two lines?
  • Of the four angles formed which of the angles are equal? What are they called?
  • Do the three intersecting lines enclose a space? How does it look? It is called a triangle.
  • What are the points of intersection of these three lines called?
  • The line segments forming the triangle are called sides.
  • How many angles are formed when three lines intersect with each other?
  • How many angles are enclosed by the triangle?

Evaluation at the end of the activity

  • Can there be a closed figure with less than three sides?
  • Can the vertices of the triangle be anywhere on a plane?
  • What will happen if the three vertices are collinear?