Answer:
the balls are larger, or don't pack as tightly
Step-by-step explanation:
The volume by either measure will depend on a couple of factors:
- the volume of the unit used (ball or cube)
- the way the units can be packed
In a rectangular space, such as a box, it may be easier to pack cubes than balls. So, more cubes of the same volume would fit simply because they can be packed closer together.
We aren't told the volume of either the cube or the ball, and we're not told the extent to which the packing is optimized.
Fewer balls may fit because their packing is not as well optimized as that of the cubes, or because each has a larger volume than the cube being used.
Answer:

Step-by-step explanation:
Factor
out of 
The answer is B
Hope this helps :)
The circumcenter is where the perpendicular bisectors meet.
if you sketch the triangle, you will see that it is a right triangle, with the right angle vertex at (2,1)
one perpendicular bisector is x=1, another perpendicular bisector is y=3
they meet at (1,3)
so (1,3) is the answer.