The constant of proportionality is the continuous ratio betwwen two variables.
Answer:
I do believe that it is B.
Sorry I don't have much of an explanation.
The answer is 60pi
The entire circle circumference covers 360 degrees.
The arc EF only takes 30 degrees.
The arc EF is 30/360 of the total circumference.
Arc EF is 5pi units.
The entire circumference is (5pi)/(30/360) = 60pi