# Angle

on . Posted in Geometry

An angle, abbreviated as $$\:A\:$$, $$\:\theta\:$$ or $$\:\angle\:$$, is formed by two lines having a common point or vertex.

## Angle formulas

$$\large{ \theta = \frac{ l_a }{ r } }$$

$$\large{ \theta = \frac{ 2 \; A_{se} }{ r^2 } }$$

Symbol English Metric
$$\large{ \theta }$$ = angle $$\large{deg}$$ $$\large{rad}$$
$$\large{ l_a }$$ = arc length $$\large{ in}$$ $$\large{ mm }$$
$$\large{ r }$$ = radius $$\large{in}$$ $$\large{mm}$$
$$\large{ A_{se} }$$ = sector area $$\large{in^2}$$ $$\large{mm^2}$$