Solve for m:C = 1/3 π d^2 m
C = 1/3 d^2 m π is equivalent to 1/3 d^2 m π = C:1/3 π d^2 m = C
Divide both sides by (π d^2)/3:Answer: m = (3 C)/(π d^2)
Hey I tried, hope it helps... can't work it out, all the best
D. I think because you would get a negative