There is a shorthand way of writing the length of an arc. R indicates the radius of the arc. For dispersion or variation of set of values try Standard Diviation Calculator.
Degrees and Radians Strictly speaking there are actually 2 formulas to determine the arc length.
One radian is the angle formed when an arc of a circle is equal in length to the radius of that circle. When the central angle is measured in degrees the arc length formula is. Thus the length of the arc AB will be 518 of the circumference of the circle which equals 2 pr according to the formula for circumference. Another way of measuring angles instead of degrees are Radians.