Symbol Name

angle

measured angle

spherical angle

right angle

degree

arcminute

arcsecond

line

ray

perpendicular

parallel

congruent to

similarity

triangle

distance

pi constant

radians

grads

Meaning / definition

formed by two rays

= 90º

1 turn = 360º

1º = 60´

1´ = 60´´

line from point A to point B

line that start from point A

perpendicular lines (90º angle)

parallel lines

equivalence of geometric shapes and size

same shapes, not same size

triangle shape

distance between points x and y

π = 3.141592654...

Example

∠ABC = 30º

∡ABC = 30º

∢AOB = 30º

α = 90º

α = 60º

α = 60º59'

α = 60º59'59''

AC | BC

AB || CD

∆ABC ≅ ∆XYZ

∆ABC ~ ∆XYZ

ΔABC ≅ ΔBCD

| x-y | = 5

c = π·d = 2·π·r

360º = 2π rad

360º = 400 grad

is the ratio between the circumference and diameter of a circle

radians angle unit

grads angle unit