8 - 11 year olds

Take some sticks, If you don't have sticks, you can cut paper strips of the following lengths: 5, 8 and 9 centimeters. Can you make a triangle, joining them at their ends?

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Try it with 3, 7 and 10 centimeters and with 4, 6 and 13 centimeters.

a-- Do you know when it is possible?

b-- Complete 11cm, 11cm, with another length less than 6 (whole number) so that it does form a triangle.

c-- Complete 11cm., 11cm, with another length, less than 6, so that it does not form a triangle.