The arc measure corresponds to the associated angle. The circular arc (b) has the same portion of the circumference (d · ), which the associated angle () has at the circumference angle (360°).

b           = d ·       360°
b·360° d=         ·	b · 360° =       d ·	d · · b=        360°

Check your calculation!     You need help? Please enter numbers only in two of the three fields!
d	Diameter		mm cm dm m
	Angle		° (grad)
b	Circular measure		mm cm dm m
Places behind the comma: 2 3 4 5

Example

Geg.: d = 115 mm; = 25°

Ges.: b in m

Answer:

        d · ·
b =
        360°

  115 mm · 3,14 · 25°
=
        360°

= 25,08 mm