Difference between revisions of "Relation between interior and exterior angles in triangle"

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An exterior angle of the triangle is the angle between one side of a triangle and the extension of an adjacent side. Exterior angle of the triangle has a relation with interiors of the triangle.
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Interior angle and the corresponding angle form a linear pair. This exterior angle in relation to the remote interior angles and their dependencies are deducted with the theorem.
  
 
=== Objectives ===
 
=== Objectives ===
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*Non digital : Worksheet and pencil.
 
*Non digital : Worksheet and pencil.
 
*Geogebra files :
 
*Geogebra files :
*#'''“[https://ggbm.at/a33ygakp a. EA= Sum of opposite IAs in a triangle proof.ggb]” ,'''
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*#'''“[https://ggbm.at/dqxt4jb3 a. EA= Sum of opposite IAs in a triangle proof.ggb]” ,'''
*#'''“[https://ggbm.at/rq7tx8kn b. EA= Sum of opposite IAs in a triangle.ggb]” ,'''
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*#'''“[https://ggbm.at/ytruqndh b. EA= Sum of opposite IAs in a triangle.ggb]” ,'''
*#'''“[https://ggbm.at/gjwtzucu c. EA= Sum of opposite IAs in a triangle demo.ggb]”'''
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*#'''“[https://ggbm.at/bt4qsh42 c. EA= Sum of opposite IAs in a triangle demo.ggb]”'''
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{{Geogebra|yweqm6bj}}{{Geogebra|ytruqndh}}{{Geogebra|bt4qsh42}}
 
===Process (How to do the activity)===
 
===Process (How to do the activity)===
 
*In the triangle students should identify the angles of the triangle.
 
*In the triangle students should identify the angles of the triangle.
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'''Evaluation at the end of the activity'''
 
'''Evaluation at the end of the activity'''
 
* Have the students able to identify the relation between  exterior and interior opposite angles of a triangle?
 
* Have the students able to identify the relation between  exterior and interior opposite angles of a triangle?
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[[Category:Triangles]]
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[[Category:Class 8]]
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[[Category:Classroom activities]]

Latest revision as of 10:37, 26 April 2019

Interior angle and the corresponding angle form a linear pair. This exterior angle in relation to the remote interior angles and their dependencies are deducted with the theorem.

Objectives

To show interior angles of a triangle have a relation with its exterior angles.

Estimated Time

40 minutes

Prerequisites/Instructions, prior preparations, if any

Prior understanding of point, lines and angles, adjacent angles, vertically opposite angles, linear pair

Materials/ Resources needed


Download this geogebra file from this link.


Download this geogebra file from this link.


Download this geogebra file from this link.


Process (How to do the activity)

  • In the triangle students should identify the angles of the triangle.
  • Extend one side, students should recognize the exterior angle formed.
  • What is the sum of the angles of a triangle?
  • Students should be able to recognize the alternate angle formed for one of the interior angle(Angle BAC)
  • Drag the parallel line to the opposite vertex, to place the alternate angle next to the angle at the opposite vertex.
  • Compare the angles formed and the exterior angle, do they have a relation.
  • How are the two angles together related to the exterior angle?
  • Do you notice any relation between the exterior angle and the interior angles
  • If you know the measure of interior angle can you find the corresponding exterior angle?
  • The other two files can be used to demonstrate the the relation between the exterior angle and opposite interior angles.
  • Note the measure of angles
Triangle Angle A Angle B Angle C Exterior angle Angle A + Angle B
Triangle1
Triangle2
Triangle3

Evaluation at the end of the activity

  • Have the students able to identify the relation between  exterior and interior opposite angles of a triangle?