Sector is bounded by two radii and a arc.
segment is bounded by 1 chord and a arc.

Introduction:
A circle is a closed figure where all points on its boundary are equidistant from its center. The sector and segment are two parts that divide a circle.

Sector:
A sector is a part of a circle enclosed by two radii and an arc. It is a fraction of a circle that is enclosed between two radii and an arc. The angle formed by the two radii at the center of the circle determines the size of the sector. Sectors can be described by their angle measure in degrees or radians. The formula for the area of a sector is A = (θ/360)πr², where θ is the angle measure in degrees and r is the radius of the circle.

Segment:
A segment is a part of a circle that is enclosed between a chord and an arc. A chord is a line segment that connects two points on the circumference of a circle. The segment is the region between the chord and the arc, including the endpoints of the chord. A segment can be described by its height and width. The formula for the area of a segment is A = (θ/360)πr² - ½r²sinθ, where θ is the angle measure in degrees and r is the radius of the circle.

Differences:
1. Definition: A sector is a part of a circle enclosed by two radii and an arc, while a segment is a part of a circle that is enclosed between a chord and an arc.
2. Shape: A sector is shaped like a slice of pie, while a segment is like a piece of pizza.
3. Angle: A sector is determined by the angle between the two radii at the center of the circle, while a segment is determined by the angle of the arc.
4. Formula: The formula for the area of a sector is A = (θ/360)πr², while the formula for the area of a segment is A = (θ/360)πr² - ½r²sinθ.

Conclusion:
In conclusion, the sector and segment are two parts that divide a circle. The sector is shaped like a slice of pie and is determined by the angle between two radii, while the segment is like a piece of pizza and is determined by the angle of the arc. The formulas for the area of a sector and segment are different.