Calculate perimeter of a regular hexagon with vertices on a circle of diameter 1 centimetre.
The figure is shown below:

Diameter of circle, CF = 1 centimetre
∴ Radius of circle =
cm = 0.5 cm
As can be seen from figure,
Radius of circle = Side of Hexagon
∴ Side of Hexagon = 0.5 cm
Perimeter of Hexagon = 6 × Side of Hexagon
= 6 × 0.5
= 3 cm