Answer
$2$
Work Step by Step
RECALL:
$\log{(10^x)}=x$
Use the rule above to obtain:
$\log{(\log{10^{100})}}=\log{100}$
Note that $100=10^2$.
Thus,
$\log{100}=\log{(10^2)}$
Use the rule in the recall part above to obtain:
$\log{(10^2)} = 2$