Arc
An arc is a part of a circle. An arc is a curved line. The curve of an arc is constant and does not change (that is, an arc has constant curvature). It sometimes is portrayed as a dotted line.
In a circle, the arc from point A to point B is written as .[1][2] We call the length of an arc an arc length. For an arc on a circle with radius subtended by an angle , its arc length is precisely .[3]