Volume of cylinder = pi r^2 h = 321
Volume of cone = 1/3 (pi r^2 h)
Since pi r^2 h are all constants (i.e. in both equations they are the same numbers) we can can say (pi r^2 h) altogether is a constant value, which we already know to be 321, therefore Volume of cone = 1/3(321) = 107 cubic units