Terminology
- Chord: a line segment whose endpoints lie on the circle.
- Diameter: the longest chord, a line segment whose endpoints lie on the circle and which passes through the centre; or the length of such a segment, which is the largest distance between any two points on the circle.
- Radius: a line segment joining the center of the circle to any point on the circle itself; or the length of such a segment, which is half a diameter.
- Circumference: the length of one circuit along the circle itself.
- Tangent: a straight line that touches the circle at a single point.
- Secant: an extended chord, a straight line cutting the circle at two points.
- Arc: any connected part of the circle's circumference.
- Sector: a region bounded by two radii and an arc lying between the radii.
- Segment: a region bounded by a chord and an arc lying between the chord's endpoints.
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