Hexagon

A hexagon is a 6-sided polygon (a flat shape with straight sides): 

Soap bubbles tend to form hexagons
when they join up.

Honeycomb has hexagons too!

Regular or Irregular

When all angles are equal and all sides are equal it is regular, otherwise it is irregular:

Regular Hexagon	Irregular Hexagons

Concave or Convex

A convex hexagon has no angles pointing inwards. More precisely, no internal angles can be more than 180°.

When any internal angle is greater than 180° it is concave. (Think: concave has a "cave" in it)

Convex Hexagon	Concave Hexagon

Is it a Hexagon?

No curved sides. And the shape must also be closed (all the lines connect up):

Hexagon (straight sides)	Not a Hexagon (has a curve)	Not a Hexagon (open, not closed)

Properties

A regular hexagon has:

• Interior Angles of 120°
• Exterior Angles of 60°
• Area = (1.5√3) × s² , or approximately 2.5980762 × s² (where s=side length)
• Radius equals side length

The radius is the side length.
It is also made of 6 regular triangles!

Any hexagon has:

• Sum of Interior Angles of 720°
• 9 diagonals

More Images

Hexagonal nuts and bolts are easy to grip with a wrench,
which can be re-positioned every 60° if needed.

There is a huge hexagon on Saturn,
it is wider than Earth.

Another image of the hexagon on Saturn.

Snowflakes have hexagonal patterns, like this beautiful image from NASA.
Photograph by NASA / Alexey Kljatov.

Also a snowflake!
Photograph by NASA / Alexey Kljatov.