A sphere with a diameter of 9 units fits exactly in the clear glass cube as shown. A sphere is inside of a cube. The cube has side lengths of 9 units. Which expression represents the volume, in cubic units, of empty space in the cube? four-thirdsπ(4. 53) – (4. 5)3 (9)3 – four-thirdsπ(4. 52) four-thirdsπ(4. 53) – (9)3 (9)3 – four-thirdsπ(4. 53).