Arc Length

The arc length is the length of the part of the circle's circumference that is defined by the arc. It is like measuring the length of a straight line, but instead, it follows a curved path.

The arc length is not to be confused with the arc measure. The former measures distance, in linear units like inches and centimeters, while the later is measured using degrees or radians. In the diagram, the measure of AB equals θ, while the length of AB corresponds to the portion of the circumference the red arc spans.

The arc length can be calculated using the relationship between the arc length and arc measure.