Answer
$7.98 \times 10^{12} m^{3}$
Work Step by Step
Width = $118 mi = 118\times 1609.3m=189897.4m$
Length = $307 mi = 307\times 1609.3m=494055.1m$
Depth = $279 ft = 279\times 0.3048m=85.0392m$
So, Volume = $Width\times Length \times Depth$
$= 7.98 \times 10^{12} m^{3}$