Table of symbols in geometry:
| 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 |