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Today Puzzle #566

Puzzle No. 566– Wednesday 12 September

An ant crawls on the surface of an vertical cylinder, 6 cm in circumference and 4 cm high. She starts at a point on the bottom edge of the cylinder and wishes to reach the diametrically opposite point on the top edge of the cylinder. What is the length of the shortest route between these two points?

Today’s #PuzzleForToday has been set by Dr Gihan Marasingha, Senior Lecturer in mathematics at the University of Exeter

Click here for the answer

5 cm. Make a cut vertically up from the start point and flatten the cylinder. The shortest route between the two points is a straight line. Pythagoras' Theorem gives the length of this line.

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