# Sector angle and segment area just given only 2 variables ?

1. May 17, 2008

### CGUE

Is there a way to calculate the sector angle and segment area of a circle just given only the radius and the length of the circle ?
So far I can only calculate the sagitta length using the radius and length of the chord i.e.

$$S = r - \sqrt{r^2 - \frac{1}{2}l^2}$$

Where r is the radius of the circle and l is the length of the chord.

2. May 17, 2008

### tiny-tim

Hi CGUE !

sin = opp/hyp …

sin 1/2 sector angle = 1/2 l/r