Geometry symbols

Geometry and trigonometry are branches of mathematics concerned with geometrical figures and angles of triangles. The following list documents some of the most notable symbols in these topics, along with each symbol’s usage and meaning.

For readability purpose, these symbols are categorized by their function into tables. Other comprehensive lists of math symbols — as categorized by subject and type — can be also found in the relevant pages below (or in the navigational panel).

In geometry, points and lines form the foundation of more complex geometrical figures such as triangles, circles, quadrilaterals and polygons. The following table documents some of the most notable symbols related to these — along with each symbol’s meaning and example.

Table of symbols in geometry:

Symbol	Symbol Name	Meaning / definition	Example
∠	angle	formed by two rays	∠ABC = 30°
	measured angle		ABC = 30°
	spherical angle		AOB = 30°
∟	right angle	= 90°	α = 90°
°	degree	1 turn = 360°	α = 60°
deg	degree	1 turn = 360deg	α = 60deg
′	prime	arcminute, 1° = 60′	α = 60°59′
″	double prime	arcsecond, 1′ = 60″	α = 60°59′59″
	line	infinite line
AB	line segment	line from point A to point B
	ray	line that start from point A
	arc	arc from point A to point B	= 60°
⊥	perpendicular	perpendicular lines (90° angle)	AC ⊥ BC
∥	parallel	parallel lines	AB ∥ CD
≅	congruent to	equivalence of geometric shapes and size	∆ABC ≅ ∆XYZ
~	similarity	same shapes, not same size	∆ABC ~ ∆XYZ
Δ	triangle	triangle shape	ΔABC ≅ ΔBCD
|x-y|	distance	distance between points x and y	| x-y | = 5
π	pi constant	π = 3.141592654... is the ratio between the circumference and diameter of a circle	c = π⋅d = 2⋅π⋅r
rad	radians	radians angle unit	360° = 2π rad
c	radians	radians angle unit	360° = 2π c
grad	gradians / gons	grads angle unit	360° = 400 grad
g	gradians / gons	grads angle unit	360° = 400 g

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