Volume of a Cylinder: πr² * h
Work:
3.14 * 5² = 78.5
78.5 * 16 = 1,256
Since a cone is 1/3 the volume of a cylinder, all you have to do is find 2/3 the volume of a cone to find the air space surrounding the cone inside the cylinder.
1,256 * 2/3 = 837.33333.......
I hope this helped!