Today Puzzle #566
![](https://ichef.bbci.co.uk/images/ic/256xn/p057chtw.jpg)
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.
![](https://ichef.bbci.co.uk/images/ic/256xn/p055ptd0.jpg)
-
Puzzle for Today – Index
Find all of the currently available Puzzles for Today, with answers.
![](https://ichef.bbci.co.uk/images/ic/256xn/p055ptd0.jpg)
More fiendish brain-teasers and quizzes on ´óÏó´«Ã½ Radio...
-
From autumn leaves to the magic roundabout: test yourself with our favourite quizzes.
-
We asked the intelligence agency to set our listeners a code-cracking challenge... Can you solve it?
-
Quiz: How many of these Mastermind music questions can you answer?
Here's a chance to find out whether your specialist subject on Mastermind could be the entire history of music.
-
Six conundrums to grapple with, including the Riddle of the Sphinx. Try not to forfeit your life...