A wire in the shape of an equilateral triangle with sides of length 9cm is placed flat on a piece of paper.
A pencil is held in the hole at the centre of a disc of radius 1cm, and the disc is rolled all the way around the outside of the wire, and then all the way around the inside of the wire. What shape is drawn by the pencil?
Select one option, then click Submit.
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Select an option, then submit.
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Intermediate Mathematical Challenge 2000 (2000)
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