Theory:

A circle is one of the geometrical shapes which has no corners or edges.
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Parts of the circle:
 
Circumference: The distance once around the circle.
 
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Circular arc: A part of the circumference of a circle AB.
 
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Sector: The plane surface that is enclosed between two radii (\(r\)) and the circular arc of a circle AB.
 
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Chord: A line segment joins any two-point \(A\) and \(B\).
 
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Diameter: A chord \(A\) and \(B\) passing through the centre of a circle \(O\). It also knowns as the longest chord.
 
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Radius: A distance from the centre \(O\) to the circumference.
 
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Segment: A chord divide the circle into two parts. Each part is termed as segments. In this, the smaller arc is known as a minor segment, and the larger arc is known as a major segment.
 
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Concentric circles: A circle has the same centre but different radii.
  
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