Let's recall the formula of the volume of a sphere:
Volume = 4/3 * π * r3
Now, we can calculate the volume of a hemisphere that is half of a sphere:
Volume = 2/3 * π * r3
Now, we can replace the value of the radius given, as follows:
Volume = 2/3 * π * 74,618.46 cubic feet
Volume = 154,639.3 cubic feet