Hexagon.
If it's interior angle is a factor of 360 then it will tessellate such as a square, a regular hexagon and an equilateral triangle.
An [equilateral] triangle, square and hexagon are the only regular polygons which, by themselves, will tile a surface.
Equilateral triangle, square and regular hexagon.
Triangle, square and hexagon
Equilateral triangle, square and regular hexagon.
Triangle, square, hexagon.
If it's interior angle is a factor of 360 then it will tessellate such as a square, a regular hexagon and an equilateral triangle.
square, equillateral triangle, & regular hexagon
Triangle, square, hexagon.
An [equilateral] triangle, square and hexagon are the only regular polygons which, by themselves, will tile a surface.
Equilateral triangle, square and regular hexagon.
Triangle, square and hexagon
Equilateral triangle, square and regular hexagon.
Equilateral triangle, square and regular hexagon.
Most regular polygons will not - by themselves. In fact, of the regular polygons, only a triangle, square and hexagon will. No other regular polygon will create a regular tessellation.
In a normal plane, only regular polygons with interior angles that are a factor of 360o can be tessellated. This means only three shapes: the regular (equilateral) triangle, the regular quadrilateral (square) and the regular hexagon. If the line were considered a regular polygon (with only two sides) then it would also be included in this list.
If they are both regular polygons then it is the octagon which is 135 degrees whereas the hexagon is 120 degrees