883
edits
Changes
From Karnataka Open Educational Resources
→Activity No # 7 :Angle sum property
<nowiki>-----------------</nowiki>
* '''Evaluation at the end of the activity'''
* '''Evaluation at the end of the activity'''
# Are children able to recognize the types of triangles when the sides are specified.
# Are children able to recognize the types of triangles when the sides are specified.
=== '''Activity No # 7 :Angle sum property''' ===
=== '''Activity No # 7 :Angle sum property''' ===
* '''Objectives'''
# To establish the angle sum property of a triangle
# To help visualization of the geometric proof
* '''Pre-requisites'''
Prior understanding of point, lines and angles, adjacent angles, vertically opposite angles, linear pair, parallel lines, alternate angles, corresponding angles.
* '''Resources needed'''
1. Digital : Computer, geogebra application, projector.
2. Non digital : Worksheet and pencil.
3. Geogebra files : '''“7a. Angles in a right triangle.ggb” , “7b. Angle sum property proof.ggb” , “7c. Angle sum property of a triangle.ggb”'''
* '''How to do'''
# Use the file - “7a. Angles in a right triangle.ggb”
# Ask students what is the kind of triangle they observe.
# Draw a parallel line to the side containing the right angle through the opposite vertex by dragging point D along the x-axis
# Students should be able to recognize the corresponding angles formed when the parallel line is drawn.
# Students should be able to recognize the alternate angles formed. Is the alternate angle same as one of the angles of the triangle.
# So what can you say about the all the angles of the triangle?
# With the file - “7b. Angle sum property proof.ggb”
# Draw a line perpendicular to a side passing through the opposite vertex. How many triangles are formed. What kinds of triangles are formed?
# In each of the two triangles if on angle is 90<sup>o</sup>, what will be the sum of the other two angles. What is the sum of these angles?
# Children can record the values of the angles of a triangle in the worksheet
<nowiki>--------------</nowiki>
# With the file – “7c. Angle sum property of a triangle.ggb”
# Ask students what happens when the three angles of the triangle are placed adjacent to each other.
# What can you say about the line drawn?
# Is it parallel to one of the sides?
# What can you say about the pairs of angles – look at the matching colors.
# Once the parallel line reaches the vertex, how many angles are formed?
# Students should be able to identify the two angles moving are corresponding angles as the line moving is parallel to one of the sides.
# Students can see that when the three angles of the triangle are placed adjacent to each other they form a straight line.
<nowiki>--------------</nowiki>
* Evaluation at the end of the activity
# Have students able to conclude if the sum of angles in any triangle is 180<sup>o</sup>?
== Concept 4: Relation between interior and exterior angles in a triangle ==
=== '''Activity No # 8 : Relation between interior and exterior angles in a triangle''' ===
* '''Objectives'''
1. To show interior angles of a triangle have a relation with its exterior angles.
* '''Pre-requisites'''
Prior understanding of point, lines and angles, adjacent angles, vertically opposite angles, linear pair
* '''Resources needed'''
1.Digital : Computer, geogebra application, projector.
2. Non digital : Worksheet and pencil.
3. Geogebra files : '''“8a. EA= Sum of opposite IAs in a triangle proof.ggb” ,“8b. EA= Sum of opposite IAs in a triangle.ggb” ,“8c. EA= Sum of opposite IAs in a triangle demo.ggb”'''
* '''How to do''' 1. In the triangle students should identify the angles of the triangle. 2. Extend one side, students should recognize the exterior angle formed. 3. What is the sum of the angles of a triangle? 4. Students should be able to recognize the alternate angle formed for one of the interior angle(Angle BAC) 5. Drag the parallel line to the opposite vertex, to place the alternate angle next to the angle at the opposite vertex. 6. Compare the angles formed and the exterior angle, do they have a relation. 7. How are the two angles together related to the exterior angle? 8. Do you notice any relation between the exterior angle and the interior angles 9. If you know the measure of interior angle can you find the corresponding exterior angle? 10. 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
Work sheet
<nowiki>--------------</nowiki>
* Evaluation at the end of the activity 1. Have the students able to identify the relation between exterior and interior opposite angles of a triangle?
