GEOMETRIC REASONING

Exploring Matchstick Shapes

Task 1

Make a triangle, a square and pentagon using the matchsticks and valve tubes.




Make joints-of-two as shown using matchsticks and cycle valve tubes to make the shapes. Make sure the sticks are inserted properly in the tubes to form the joints!

Task 2

Perform these actions (mentioned in the table) on the square. Discuss in your group whether the shape changes or not and note it down.

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What, according to you, is ‘shape’? What causes a ‘shape’ to change?

Task 3

Try pressing on the opposite vertices of the pentagon. Does it change shape? Now try pressing a vertex and a side of the triangle. Does it change shape?

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What will happen if you do the same with a hexagon? Which shape does not change when pressed? How might this property be useful to us?

Extension Task 1

Try making as many different shapes as possible by deforming/twisting the pentagon (without breaking it or opening up the joints). In particular, try to make

•     a triangle that has exactly two sides equal
•     a four sided polygon
•     a star shape

Extension Task 2

Try making a triangle in which all three sides are of different length. What would be the minimum number of matchsticks needed for this?

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