The arc of a circle is a portion of the circumference of a circle.
The arc of a circle is a portion of the circumference of a circle. Measure an arc by two methods: 1) the measure of the central angle or Central arc in degrees 2) the length of the arc itself or central angle in radians
A practical way to determine the length of an arc in a circle is to plot two lines from the arc’s endpoints to the center of the circle, measure the angle where the two lines meet the center, then solve for L by cross-multiplying the statement:
Central angle in degrees:
measure of angle in degrees/360° = L/circumference.
Length of the arc = 2πR(C/360˚)
Central angle in radians:
Circumference of the circle = 2πR ;
π ≈ 3.142
C = Central angle = ∠AOB
Length of the arc = RC
Note: The 2π/360 converts the degrees to radians.