Congruence in triangles – SSS Rule
Investigating the possibility of congruence if three sides of two triangles are congruent.
Compare sides in triangles to check for congruence
Prerequisites/Instructions, prior preparations, if any
Prior knowledge of point, lines, angles, closed figures
Materials/ Resources needed
- Digital : Computer, geogebra application, projector.
- Non digital : Worksheet and pencil, triangles of same and different shapes
- 3. Geogebra files : “SSS congruence.ggb”
Download this geogebra file from this link.
Process (How to do the activity)
Prior hands on activity
- Three triangles are distributed to groups of students.
- Children should identify the triangles that are congruent.
- They can name the vertices in the given triangles.
- Write down the sides and angles that are coinciding in the two triangles.
Use the geogebra file
- How many triangles you observe?
- Are all the triangles same, point out the triangles that are same.
- How can you say they are same? What can you do to check if the two triangles are congruent?
- What parameters of triangles are required to know if they are congruent?
- What about the third triangle is it the same as the other two, what you should do to show the triangle is same as the others – concept pf reflection can be discussed
- Make two triangles of same sizes. Cut it and verify they are congruent.
- Construct one triangle – Base = 3, 4 and 5 are other sides. Another triangle base = 5; and two sides are 3 and 4. Another triangle base = 4; and two sides are 3 and 5. Does the order of sides matter in a triangle?
Evaluation at the end of the activity
- Students should be able to understand, if 3 corresponding sides of two triangles are same then the triangles are congruent.
- Students should also understand that the sequence of sides examined in the triangles need not be same for the triangles to be congruent.