We must calculate the length of an arc of angle 115°.
We know that the length of an arc of angle 360° is equal to: 2 pi * r.
So we can write the following formula for the lenght of an arc of angle A:

In our problem we have:
A = 115
r = 4 cm
So applying the formula of above the answer is:
![L=2\pi\cdot4\operatorname{cm}\cdot(115)/(360)=(23)/(9)\cdot\pi\cdot cm\cong8\operatorname{cm}]()
(rounded to the nearest tenth)