Difference between revisions of "Angle sum property of triangles"

Revision as of 23:36, 3 October 2021

Objectives

To establish the angle sum property of a triangle
To help visualization of the geometric proof

Estimated Time

30 minutes

Prerequisites/Instructions, prior preparations, if any

Prior understanding of point, lines and angles, adjacent angles, vertically opposite angles, linear pair, parallel lines, alternate angles, corresponding angles.

Materials/ Resources needed

Click here to open the file

Process (How to do the activity)

Download this geogebra file from this link.

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.
- 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 colours.
- 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.

Evaluation at the end of the activity

In a triangle, if the sum of two angles is 60°, then what will be the measure of third angle?
If a triangle has all three angles are equal in measure, then what will the measure of each angle?

Go back to the page - click here

@@ Line 1: / Line 1: @@
+=== Objectives ===
+* To establish the angle sum property of a triangle
+* To help visualization of the geometric proof
+=== Estimated Time ===
+minutes
+=== Prerequisites/Instructions, prior preparations, if any ===
+Prior understanding of point, lines and angles, adjacent angles, vertically opposite angles, linear pair, parallel lines, alternate angles,      corresponding angles.
+=== Materials/ Resources needed ===
+Click here to [[:File:Angle sum property of triangle.ggb|open]] the file
+=== Process (How to do the activity) ===
+{{Geogebra|xbwbcdgn}}
+* 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.
+** 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 colours.
+** 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.
+=== Evaluation at the end of the activity ===
+# In a triangle, if the sum of two angles is 60°, then what will be the measure of third angle?
+# If a triangle has all three angles are equal in measure, then what will the measure of each angle?
+Go back to the page - [https://karnatakaeducation.org.in/KOER/en/index.php/Triangles?veaction=edit&section=20 click here]
+[[Category:Triangles]]