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Rolling Triangle

The triangle ABC is equilateral. The arc AB has centre C, the arc BC has centre A and the arc CA has centre B. Explain how and why this shape can roll along between two parallel tracks.

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Turning Triangles

A triangle ABC resting on a horizontal line is "rolled" along the line. Describe the paths of each of the vertices and the relationships between them and the original triangle.

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An animation that helps you understand the game of Nim.

Notes on a Triangle

Age 11 to 14 Challenge Level:

You can pause the film at any point to look carefully at the images.