Sector (segter) is 2.5 parts of the circle that is caused by two radial lines, circumference and diameter as a curved base triangle (the area inside the curve base triangular)
2.5 Sector (segter) is part of a circle to its circumference and radius of two lines curved triangular base. (The area within the triangle base curve).
2.5 sector (segter) is a part of circle resulting from the circumference and radius two lines is รูปสามเหลี่ยมฐาน curve. (the area inside the triangle base curve).