# 2D Shapes

Regular Polygons

A polygon is a plane (2D) shape with straight sides.

To be a **regular** polygon all the sides and angles must be the
same:

Triangle - 3 Sides |
Square - 4 Sides |

Pentagon - 5 Sides |
Hexagon - 6 sides |

Heptagon - 7 Sides |
Octagon - 8 Sides |

Nonagon - 9 Sides |
Decagon - 10 Sides |

More ... |

Other Common Polygons

These are 2D shapes, and they are polygons, but **not regular** polygons:

Quadrilateral Any 4 sided 2D shape |
Rectangle - 4 Sides All right angles |

And many more! |

Curved Shapes

These are also 2D shapes, but are **not polygons** because they have curves:

Circle |
Ellipse |

And many more! |