Answer
$$213\times 10^{18}$$
Work Step by Step
By adding the exponents and multiplying the like terms, we have
$$(39.4\times 10^{6})(120\times 10^{-3})(45.0\times 10^{12})=212760\times 10^{15}\\
=213\times 10^{18}$$
which is in the engineering notation.
