- $ V = \\\frac{{\\\sqrt 2 \\\pi {a^3}}}{2}$.
- $ V = \\\frac{{\\\pi {a^3}}}{2}$.
- $ V = \\\frac{{\\\sqrt 2 \\\pi {a^2}}}{6}$.
- $ V = \\\frac{{\\\pi {a^3}}}{6}$.