A circular plate rolls in contact with the sides of a rectangular
tray. How much of its circumference comes into contact with the
sides of the tray when it rolls around one circuit?
Read all about the number pi and the mathematicians who have tried to find out its value as accurately as possible.
Tim Rowland introduces irrational numbers
By inscribing a circle in a square and then a square in a circle
find an approximation to pi. By using a hexagon, can you improve on