# List of two-dimensional geometric shapes

This is a list of two-dimensional geometric shapes in Euclidean and other geometries. For mathematical objects in more dimensions, see list of mathematical shapes. For a broader scope, see list of shapes.

## Generally composed of straight line segments

* Angle
* Balbis
* Concave polygon
* Constructible polygon
* Convex polygon
* Cyclic polygon
* Equiangular polygon
* Equilateral polygon
* Penrose tile
* Polyform
* Regular polygon
* Simple polygon
* Tangential polygon

### Polygons with specific numbers of sides

* Triangle – 3 sides
** Acute triangle
** Equilateral triangle
** Heptagonal triangle
** Isosceles triangle
*** Golden Triangle
** Obtuse triangle
** Rational triangle
** Heronian triangle
*** Pythagorean triangle
*** Isosceles heronian triangle
*** Primitive Heronian triangle
** Right triangle
*** 30-60-90 triangle
*** Isosceles right triangle
*** Kepler triangle
** Scalene triangle
* Quadrilateral – 4 sides
** Cyclic quadrilateral
** Kite
*** Rectangle
*** Rhomboid
*** Rhombus
*** Square (regular quadrilateral)
** Tangential quadrilateral
** Trapezoid
*** Isosceles trapezoid
** Trapezus
* Pentagon – 5 sides
* Hexagon – 6 sides
** Lemoine hexagon
* Heptagon – 7 sides
* Octagon – 8 sides
* Nonagon – 9 sides
* Decagon – 10 sides
* Hendecagon – 11 sides
* Dodecagon – 12 sides
* Tridecagon – 13 sides
* Tetradecagon – 14 sides
* Pentadecagon – 15 sides
* Hexadecagon – 16 sides
* Heptadecagon – 17 sides
* Octadecagon – 18 sides
* Enneadecagon – 19 sides
* Icosagon – 20 sides
* Icosikaihenagon - 21 sides
* Icosikaidigon - 22 sides
* Icositrigon - 23 sides
* Icositetragon - 24 sides
* Icosikaipentagon - 25 sides
* Icosikaihexagon - 26 sides
* Icosikaiheptagon - 27 sides
* Icosikaioctagon - 28 sides
* Icosikaienneagon - 29 sides
* Triacontagon - 30 sides
* Tetracontagon - 40 sides
* Pentacontagon - 50 sides
* Hexacontagon - 60 sides
* Heptacontagon - 70 sides
* Octacontagon - 80 sides
* Enneacontagon - 90 sides
* Hectogon - 100 sides
* Dihectogon - 200 sides
* Trihectogon - 300 sides
* Tetrahectogon - 400 sides
* Pentahectogon - 500 sides
* Hexahectogon - 600 sides
* Heptahectogon - 700 sides
* Octahectogon - 800 sides
* Enneahectogon - 900 sides
* Chiliagon - 1,000 sides
* Myriagon - 10,000 sides
* Megagon - 1,000,000 sides
* Star polygon – there are multiple types of stars
** Pentagram - star polygon with 5 sides
** Hexagram – star polygon with 6 sides
*** Star of David (example)
** Heptagram – star polygon with 7 sides
** Octagram – star polygon with 8 sides
*** Star of Lakshmi (example)
** Enneagram - star polygon with 9 sides
** Decagram - star polygon with 10 sides
** Hendecagram - star polygon with 11 sides
** Dodecagram - star polygon with 12 sides
* Apeirogon - generalized polygon with countably infinite set of sides

## Curved
### Composed of circular arcs

* Annulus
* Arbelos
* Circle
** Archimedes' twin circles
** Bankoff circle
** Circular triangle
*** Reuleaux triangle
** Circumcircle
** Disc
** Incircle and excircles of a triangle
** Nine-point circle
* Circular sector
* Circular segment
* Crescent
* Lens, vesica piscis (fish bladder)
* Lune
* Quatrefoil
* Reuleaux polygon
** Reuleaux triangle
* Salinon
* Semicircle
* Tomahawk
* Trefoil
* Triquetra

### Not composed of circular arcs

* Archimedean spiral
* Astroid
* Cardioid
* Deltoid
* Ellipse
* Various lemniscates
* Oval
** Cartesian oval
** Cassini oval
** Oval of Booth
* Superellipse
* Taijitu
* Tomoe
* Magatama