Difference between revisions of "Interior and exterior angles in triangle"

Latest revision as of 06:45, 4 November 2019

Angles are formed when three lines intersect with each other. There are angles that are enclosed by the three lines and there are angles that are formed outside the closed figure.

Objectives

Identify all angles when a triangle is formed
Understand the relation between various angles that are formed in a triangle.

Estimated Time

Prerequisites/Instructions, prior preparations, if any

Prior knowledge of point, lines, angles

Materials/ Resources needed

Digital : Computer, geogebra application, projector.
Non digital : Worksheet and pencil.
Geogebra files : “Angles of triangle.ggb”

Download this geogebra file from this link.

Process (How to do the activity)

Ask students how many lines are there? They should be able to identify the points of intersection of the lines. How many points of intersection are formed?
How many angles are formed at an intersecting point? How many angles in total at the three points of intersection?What is the total angle measure at each intersecting point?
How many angles are inside the triangle and how many are outside the triangle
Can you find an exterior angle that is equal to the interior angle of a triangle at each vertex?Why are they equal?
Identify the exterior angles that are equal? Justify why they are equal.
Establish that there are 2 angles which are exterior of the triangle that are equal and are formed when the sides of the triangle is extended at the vertex.
Students to analyze the interior and exterior angle at each point to find a relation between the interior angle and one of the exterior angles at the vertex. Students should be able to recognize the linear pair formed by interior angle and exterior angle.
Vary the position of the lines to check if interior and exterior angles form a linear pair.

Note the measure of angles

Angles of the triangle			Exterior angle			Interior angle + Exterior angle
Angle 1	Angle 2	Angle 3	Angle 1	Angle 2	Angle 3	In Angle 1 + Ex Angle1	In Angle 2 + Ex Angle2	In Angle 3 + Ex Angle3
.
.

Evaluation at the end of the activity

Are students able to recognize interior and exterior angles in a triangle
Have the students able to find a relation between the interior angle and exterior angle that are formed at each vertex?

@@ Line 1: / Line 1: @@
-===Name of the activity===
+Angles are formed when three lines intersect with each other. There are angles that are enclosed by the three lines and there are angles that are formed outside the closed figure.
-Brief blurb describing what the activity.  If this has been borrowed from some external web site (for example, a non OER or OER site which had this idea and based on which the activity was developed)
 === Objectives ===
-Content objectives  - what content areas
+*Identify all angles when a triangle is formed
+*Understand the relation between various angles that are formed in a triangle.
-Skill objectives - what specific skills
-Classroom objectives - to demo peer learning, to make a classroom resource, etc -
-All these kinds of objectives need not be there for every activity.  And no need to list them as different headings.  This is only for our reference when we are developing activities.
 ===Estimated Time===
 === Prerequisites/Instructions, prior preparations, if any ===
+Prior knowledge of point, lines, angles
 ===Materials/ Resources needed===
+*Digital : Computer, geogebra application, projector.
+*Non digital : Worksheet and pencil.
+*Geogebra files :  '''“[https://ggbm.at/xt5tcf6t Angles of  triangle.ggb]”'''
+{{Geogebra|xt5tcf6t}}
 ===Process (How to do the activity)===
-How to do the different steps of the activity?
+*Ask students how many lines are there? They should be able to identify the points of intersection of the lines. How many points of   intersection are formed?
+*How many angles are formed at an intersecting point? How many angles in total at the three points of intersection?What is the total   angle measure at each intersecting point?
-What kinds of questions you can ask for that activity
+*How many angles are inside the triangle and how many are outside the triangle
+*Can you find an exterior angle that is equal to the interior angle of a triangle at each vertex?Why are they equal?
-What are the student follow-up activities/ questions you can give?
+*Identify the exterior angles that are equal? Justify why they are equal.
+*Establish that there are 2 angles which are exterior of the triangle that are equal and are formed when the sides of the triangle is   extended at the vertex.
+*Students to analyze the interior and exterior angle at each point to find a relation between the interior angle and one of the exterior angles at the vertex. Students should be able to recognize the linear pair formed by interior angle and exterior angle.
+*Vary the position of the lines to check if interior and exterior angles form a linear pair.
-Categories:  (Subject) (Topic) (Sub-concept/topic) (Class 6) (Resource format)
+* Note the measure of angles
+{| class="wikitable"
+! colspan="3" |Angles of the triangle
+! colspan="3" |Exterior angle
+! colspan="3" |Interior angle + Exterior angle
+|-
+|Angle 1
+|Angle 2
+|Angle 3
+|Angle 1
+|Angle 2
+|Angle 3
+|In Angle 1 +
+Ex Angle1
+|In Angle 2 +
+Ex Angle2
+|In Angle 3 +
+Ex Angle3
+|-
+|.
+|
+|
+|
+|
+|
+|
+|
+|
+|-
+|.
+|
+|
+|
+|
+|
+|
+|
+|
+|}
+'''Evaluation at the end of the activity'''
+*Are  students able to recognize interior and exterior angles in a  triangle
+*Have  the students able to find a relation between the interior angle and  exterior angle that are formed at each vertex?
-Example -  (Mathematics) (Triangle) (Area) (Perimeter) (Class 6) (Class 8) (Geogebra) (Video)
+[[Category:Triangles]]
+[[Category:Class 8]]