Practice finding the volume of a sphere. The formula is Volume = 4⁄3 × π × r³.
Cube the radius, multiply by π, then by 4⁄3: V = 4⁄3 × π × r³. With a radius of 3 (π ≈ 3.14), the volume is 4⁄3 × 3.14 × 27 = 113.04 cubic units.
Cubles kits are geometry in your hands: nets, faces, edges and vertices that fold and click into a poseable 3D character. No scissors, no glue, about 15 minutes.