Final answer:
A sector is a region enclosed by two radii of a circle and the arc between them. It is named by the radius of the circle and the central angle of the sector.
Step-by-step explanation:
A sector is just like a fillet except it is an exterior arc. In geometry, a sector is a region enclosed by two radii of a circle and the arc between them. It is represented by a portion of a circle and is named by the radius of the circle and the central angle of the sector.
For example, if we have a circle with a radius of 5 units and a central angle of 60 degrees, the corresponding sector will be a slice of the circle with an arc length of 60/360 times the circumference of the circle.
So, a sector is another way to divide a circle into parts, but instead of an interior arc (fillet), it has an exterior arc.