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From Karnataka Open Educational Resources
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# What will happen if the three vertices are collinear?
# What will happen if the three vertices are collinear?
==== '''Activity No # 2 : Elements of a Triangle''' ====
* '''Objectives'''
# To understand the elements of a triangle
* '''Pre-requisites'''
Prior knowledge of point, lines, angles, parallel lines
* '''Resources needed'''
# Digital : Computer, geogebra application, projector.
# Non digital : Worksheet and pencil,6-8 strings (preferably in different colours)
# Geogebra files : “2. Elements of a triangle.ggb”
* '''How to do'''
# Students work individually but in their groups.
# Take the strings and place them in such a way as to make a closed figure.
# What is the smallest number of strings with which you can form a closed figure?
# What is this figure called?
# Can you just draw the lines along the strings and see what you get?
# When you drew, what did you draw? (Was it a line or was it an angle or was it a line segment?). It is a lime segment – how many line segments are there?
# When two line segments joined, what is it called? (A vertex). How many vertices are there?
# Is there any angle formed when you made this figure? How many angles were formed?
# Show a simple Geogebra file with triangles – Use this file to demonstrate that every triangle has the elements - vertices, sides and angles
# How many triangles were formed? Were there any strings left over?
# For each of the triangles trace the shape on the book and write down the elements of the triangle in the following format {| class="wikitable" !Vertices !Sides !Angles |- | | | |- | | | |- | | | |}
# For each of the triangles observe (inspect visually) which is the longest side and which is the shortest side {| class="wikitable" !Triangle name !Largest angle !Largest side !Smallest angle !Smallest side |- | | | | | |- | | | | | |- | | | | | |}
# Allow the students to explore if there is any connection between the two?
# After the students see the Geogebra file, they can attempt an alternative worksheet like below: {| class="wikitable" !Side 1 !Angle 1 (opposite angle) !Side 2 !Angle 2 (opposite angle) !Side 3 !Angle 3 (opposite angle) !Largest side and angle ex-side1,angle1 !Smallest side and angle ex-side3,angle3 |- | | | | | | | | |- | | | | | | | | |- | | | | | |}
'''Evaluation at the end of the activity'''
1. Have the students been able to identify the elements in a triangle?
2. Have they been able to extrapolate any connection between the angle and side in a triangle?
[[Category:Triangles]]
[[Category:Triangles]]
[[Category:Class 9]]
[[Category:Class 9]]
