# Angle

Written by Jerry Ratzlaff on . Posted in Geometry

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

### Angle Formula

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

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

Where:

$$\large{ l_a }$$ = arc length

$$\large{ r }$$ = radius

$$\large{ A_{se} }$$ = sector area