| 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 |
