# Chord of a Circle

Written by Jerry Ratzlaff on . Posted in Geometry

## Chord of a Circle

### Chord of a Circle formula

$$\large{ c = 2r \sin \frac {\theta}{2} }$$

$$\large{ c = 2 \sqrt {r^2 \;-\; h^2} }$$

$$\large{ c \; \theta = \frac{C}{r} = 2 \; \left( arccos \frac{r \;-\; h'}{r} \right) }$$

$$\large{ c \; \theta = 2 \; \left( arccos \frac{r \;-\; h'}{r} \right) }$$

Where:

$$\large{ c }$$ = chord

$$\large{ C }$$ = circumference

$$\large{ h, h' }$$ = height

$$\large{ r }$$ = radius

$$\large{ \theta }$$ = angle