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

Regular or Irregular

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

Regular Hexagon Irregular hexagonIrregular hexagon
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)

Irregular hexagon Irregular Hexagon
Convex Hexagon Concave Hexagon

Is it a Hexagon?

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

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


Regular Hexagon

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)