In searching for the arc length of a circle i stumbled upon this question and managed to do it, but I seem to be having a trouble in calculating this.
Using radians, the arc length is $l=r\theta$
And I answered $50=30\theta \Rightarrow \frac{5}{3}=\theta$ I am confused as to the radian not having any phi on it. What does this mean?
In this case, you can do two things. You can say that the arc lenght has to contain $\pi$ because it's part of a circunference and then write it as: $$\frac{50}{\pi}\pi\approx15.92\pi$$ Or, you can say, as explained before: $$\theta=\frac{5}{3}\cdot\frac{1}{\pi}\cdot\pi\approx0.531\pi$$