The formula to find the area of the segment is given below. It can also be found by calculating the area of the whole pie-shaped sector and subtracting the area of the isosceles triangle △ACB.
Where:| C | is the central angle in DEGREES |
| R | is the radius of the circle of which the segment is a part. |
| π | is Pi, approximately 3.142 |
| sin | is the trigonometry Sine function. |
If you know the segment height and radius of the circle you can also find the segment area. See Area of a Circular Segment given the Segment Height.
Use the calculator below to calculate the segment area given the radius and segment's central angle, using the formula described above. Remember: In this version, the central angle must be in degrees.
| Radius r | |
| Central angle a (degrees) | |
| Area | |