ACTIVITY 2 - TRIANGLES
Objective:
To verify the angle sum property of a triangle by paper folding.
Materials Required:
White sheets of paper, tracing paper, geometry box, a pair of scissors, etc.
Procedure:
On a white sheet of paper, draw a fairly large triangle ABC. Using scissors, cut it out. Mark A, B and C on both sides of the cutout.
2. Fold the side BC of ∆ABC such that the folding line passes through A.
3. Unfold it and draw a line along the crease. This line cuts BC at D.
4. Fold the vertices (three corners) of ∆ABC such that A, B and C meet at D.
Observations:
In figure 4, we see that the angles A, B and C form a straight angle
i.e., ∠A + ∠ B + ∠ C = 180°
Conclusion:
From the above activity, it is verified that the sum of the angles of a triangle is 180 °
Do Yourself:
Draw an acute angled triangle, a right angled triangle. By paper folding, verify the angle sum property in each case.
