The volume of the region between concentric spheres of radii r=2r = 2r=2 and R=4R = 4R=4 is:
224π3\frac{224\pi}{3}3224π
256π3−32π3\frac{256\pi}{3} - \frac{32\pi}{3}3256π−332π
72π72\pi72π
56π56\pi56π