The length of an arc with measure x in a circle with diameter d is given by:
[tex]l=2\cdot\pi\cdot(\frac{d}{2})\cdot(\frac{x\degree}{360\degree})[/tex]
Therefore, if d = 10 cm and x = 72°, we have:
[tex]l=2\cdot\pi\cdot(\frac{10}{2})\cdot(\frac{72\degree}{360\degree})\approx6.3\text{ cm}[/tex]
