Names of Shapes

Names of Shapes

Polygon - A two dimensional closed plane figure bounded by straight sides.

Simple polygon - Has only one boundary which does not cross over itself
Complex polygon - Has lines which intersect themselves
Regular polygon - All angles and sides are equal
Irregular polygon - Sides and angles are not equal
Convex polygon - Has no angles inwards pointing. No internal angles can be more than 180°
Concave polygon - Has at least one internal angle greater than 180°

Polyhedron - A 3-dimensional solid bounded by polygons. The plural of Polyhedron is Polyhedra.

Polygons

Name	Alternate names	Sides	Internal Angles (Regular Polygons Only)
Henagon	Monogon	1
Digon		2
Triangle	Trigon	3	60° / Total 180°
Quadrilateral	Tetragon	4	90° / Total 360°
Pentagon		5	108°
Hexagon		6	120°
Heptagon	Septagon	7	128.571°
Octagon		8	135°
Enneagon	Nonagon	9	140°
Decagon		10	144°
Hendecagon	Undecagon	11	147.273°
Dodecagon		12	150°
Tridecagon	Triskaidecagon	13	152.308°
Tetradecagon	Tetrakaidecagon	14	154.286°
Pentadecagon	Quindecagon Pentakaidecagon	15	156°
Hexadecagon	Hexakaidecagon	16	157.5°
Heptadecagon	Heptakaidecagon	17	158.824°
Octadecagon	Octakaidecagon	18	160°
Enneadecagon	Enneakaidecagon Nonadecagon	19	161.053°
Icosagon		20	162°
Icosihenagon		21	162.857°
Triacontagon		30	168°
Tetracontagon		40	171°
Pentacontagon		50	172.8°
Hexacontagon		60	174°
Heptacontagon		70	174.857°
Octacontagon		80	175.5°
Enneacontagon		90	176°
Hectagon	Hectogon	100	176.4°
Chiliagon		1,000	179.64°
Myriagon		10,000	179.964°
Decemyriagon		100,000	179.996°
Hecatommyriagon	Hekatommyriagon Megagon	1,000,000	~180°
Googolgon		10¹⁰⁰	~180°
n-gon		n	(n-2) x 180° / n

Polyhedra