Geometry & Trigonometry Symbols

Geometry & Trigonometry

Symbols used to describe shapes, angles, and spatial relationships.

Symbol	Name	Meaning / Usage
$\pi$	Pi	The ratio of a circle's circumference to its diameter ( $\pi \approx 3.14159$ ).
$°$	Degree	Measure of angle ( $90°$ ).
$\angle$	Angle	Denotes an angle ( $\angle ABC$ ).
$\perp$	Perpendicular	Lines meeting at a $90°$ angle ( $AB \perp CD$ ).
$\parallel$	Parallel	Lines that never intersect ( $AB \parallel CD$ ).
$\triangle$	Triangle	Represents a triangle shape ( $\triangle ABC$ ).
$\cong$	Congruent	Same shape and size (geometric equality) ( $\triangle ABC \cong \triangle DEF$ ).
$\sim$	Similar	Same shape but different size ( $\triangle ABC \sim \triangle DEF$ ).
$\theta$	Theta	Common variable for an unknown angle ( $\theta = 45°$ ).