Volume of the first dwarf planet (r₁ = 832 mi):

Volume of the second dwarf planet (r₂ = 829 mi):

So difference between the volumes is:

or if we want exact value (we use (a³-b³) = (a-b)(a²+ab+b²) ):
Well since you're using 3/8 and you need to make 4 batches, you need to multiply 3/8 with 4 it would equal 12/8 or 1 4/8 (I could be wrong but this is my answer hopefully this helps) :) <span />
Multiply both sides by 10...
So u = 50/11 = 4.5454... = 4.55
216 divided by 3 is 72 so making the answer
1/72