Answer:
π
V-foam = 4r³( 2 - ----- )
3
Step-by-step explanation:
Let the radius of the sphere be r. Then the volume of the sphere is
V = (4/3)(π)(r³).
Next, recognize that the side length of the cube is 2r, and that the volume of the cube is thus
V = (2r)³, or 8r³.
Then the volume of the foam is equal to the volume of the cube less the volume of the sphere:
V-foam = 8r³ - (4/3)(π)(r³). This could be factored into
π
V-foam = 4r³( 2 - ----- )
3