| Symbol |
Symbol Name |
Meaning / definition |
Example |
|
∠ |
angle |
formed by two rays |
∠ABC = 30º |
|
∡ |
measured angle |
|
∡ABC = 30º |
|
∢ |
spherical angle |
|
∢AOB = 30º |
| ∟ |
right angle |
= 90º |
α = 90º |
|
º |
degree |
1 turn = 360º |
α = 60º |
|
´ |
arcminute |
1º = 60´ |
α = 60º59' |
|
´´ |
arcsecond |
1´ = 60´´ |
α = 60º59'59'' |
|
AB |
line |
line from point A to point B |
|
 |
ray |
line that start from point A |
|
|
| |
perpendicular |
perpendicular lines (90º
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 |
360º
= 2π rad |
| grad |
grads |
grads angle unit |
360º
= 400 grad |