- $ S = 35{\\\text{\\\pi }}\\\,\\\left( {{\\\text{c}}{{\\\text{m}}^{\\\text{2}}}} \\\right)$.
- $ S = 70{\\\text{\\\pi }}\\\,\\\left( {{\\\text{c}}{{\\\text{m}}^{\\\text{2}}}} \\\right)$.
- $ S = \\\frac{{70}}{3}{\\\text{\\\pi }}\\\,\\\left( {{\\\text{c}}{{\\\text{m}}^{\\\text{2}}}} \\\right)$.
- $ S = \\\frac{{35}}{3}{\\\text{\\\pi }}\\\,\\\left( {{\\\text{c}}{{\\\text{m}}^{\\\text{2}}}} \\\right)$.