Answer:
it depends
Explanation:
The formula for calculating the volume of a void is the same as the formula for calculating the same shape solid. If the void is cylindrical, use the formula for the volume of a cylinder. If the void is spherical, use the formula for the volume of a sphere.
Of course, you need to know the relevant dimensions of the void.
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The volume of the cylinder with a void is the difference between the volume of a solid cylinder and the volume of the void.