There is more than one way to respond here.
I chose to leave (4^4)(5^4) as is and focus on finding an equivalent or two to
(2^5)(10^5). Note that (2^5)(10^5) factors as follows: (2^5)([2^5*5^5], or (2^5)*(2^5)*5^5
which in turn is equivalent to (2^10)*(5^5). Comparing this result to the original (4^4)(5^4), it's obvious that (2^5)(10^5) and its equivalents are larger than (4^4)(5^4).