Geometry Symbols

Geometry (Ancient Greek: geo- "earth", -metria "measurement") is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space. It is one of the oldest mathematical sciences. Initially a body of practical knowledge concerning lengths, areas, and volumes, in the 3rd century BC, Geo-metry was put into an axiomatic form by Euclid, whose treatment—Euclidean geo-metry—set a standard for many centuries to follow. Archimedes developed ingenious techniques for calculating areas and volumes, in many ways anticipating modern integral calculus. The field of astronomy, especially mapping the positions of the stars and planets on the celestial sphere and describing the relationship between movements of celestial bodies, served as an important source of geometric problems during the next one and a half millennia. A mathematician who works in this field is called a geo-meter.
Note : During the proofs in geometry congruence of triangle, if we mark the same sign on sides of two different triangles that means that two sides are congruent with each other.Similarly, if the same sign on angles of two different triangles or same triangles then that two angles are congruent to each other.

Symbol	Symbol Name	Meaning/Definition	Example
1) ∠	Angle	formed by two rays	∠ABC = 60o
2) ⊾	Right angle	90o	α = 90o
3) ≅	Congruent to	Equivalence of geometric shapes and size	ΔABC ≅ ΔPQR
4) ⊥	Perpendicular	Perpendicular lines (90o angle)	PQ ⊥ PR
5) Δ	Triangle	Triangle shape	ΔABC = ΔXYZ
6) →	Ray	Line that start from point.
7) o	Degree.	1trun = 360o	α = 60o
8) π	pi constant	π= 3.141592654...is the ratio between the circumference and diameter of a circle.	d = 2 πr
9) ∥	Parallel	Parallel lines	AB ∥ PQ
10) ∢	Spherical angle	∢ ABC = 30o

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