# Geometry Symbols

Geometry is a branch of mathematics that deals with the properties of configurations of geometric objects – (straight) lines, circles and points being the most basic.

The area of mathematics that deals with space, lines, shapes and points

Plane Geometry is about flat shapes like triangles, circles, and lines,

Solid Geometry is about solid (3-dimensional) shapes like spheres and cubes.

Let’s explore the typical Geometry symbols used in both basic Geometry and more advanced levels.

##### Example
$\angle$

measured angle

ABC = 30º
angle formed by two rays ∠ABC = 30º
right angle = 90º α = 90º
spherical angle AOB = 30º
´ arcminute 1º = 60´ α = 60º59′
º degree 1 turn = 360º α = 60º
´´ arcsecond 1´ = 60´´ α = 60º59’59”
$\overrightarrow{AB}$< ray line that start from point A
AB line segment line from point A to point B
| perpendicular perpendicular lines (90º angle) AC | BC
congruent to equivalence of geometric shapes and size ∆ABC ≅∆XYZ
|| parallel parallel lines AB || CD
Δ triangle triangle shape ΔABC ≅ΔBCD
~ similarity same shapes, not same size ∆ABC ~∆XYZ
π pi constant π = 3.141592654…

is the ratio between the circumference and diameter of a circle

c = π·d = 2·π·r
|xy| distance distance between points x and y | xy | = 5
grad grads grads angle unit 360º = 400 grad
rad radians radians angle unit 360º = 2π rad

#### Practise This Question

A=152314223 .The following elementary transformations are applied on the matrix A in the given order. What will be the resultant matrix?

1. R2 R2R3
2. R1 R1R2
3. R3 R3 – 2R2