Segment lengths in circles

 A sector is a region bounded by two radii and an arc lying between the radii, and a segment is a region bounded by a chord and an arc lying between the chord's endpoints. When two chords intersect in the interior of a circle, each chord is divided into two segments which are called segments of a chord. If two chords intersect in the interior of a circle, then the product of the lengths of the segment of one chord is equal to the product of the lengths of the segments of the other chord. If two secant segments share the same endpoint outside a circle, then the product of the length of one secant segment and the length of its external segment equals the product of the length of the other secant segment and the length of its external

segment. If a secant segment and a tangent segment share an endpoint outside a circle, then the product of the length of the secant segment and the length of its external segment equals the square of the length of the tangent segment. There are two main slices of a circle: The pizza slice is called a Sector. And the slice made by a chord is called a Segment. The Quadrant and Semicircle are two special types of Sector:

Quarter of a circle is called a Quadrant. Half a circle is called a Semicircle

The Area of a Segment is the area of a sector minus the triangular piece.

The products of the intersecting segments of chords are equal.

The product of the length of a secant segment and its external segment equal the product of the lengths of the other secant segments. Intersecting tangent and secant Tangent squared = product of secant segments