1. **Problem statement:** Calculate the volume and surface area of a hemispherical water tank with radius $r=3$ meters. 2. **Formulas:** - Volume of a hemisphere: $$V = \frac{2}{3} \pi r^3$$ - Surface area of a hemisphere (outer shell including base): $$A = 3 \pi r^2$$ 3. **Calculate the volume:** $$V = \frac{2}{3} \pi (3)^3 = \frac{2}{3} \pi \times 27 = 18 \pi$$ 4. **Calculate the surface area:** $$A = 3 \pi (3)^2 = 3 \pi \times 9 = 27 \pi$$ 5. **Final answers:** - Volume: $$18 \pi \approx 56.55$$ cubic meters - Surface area: $$27 \pi \approx 84.82$$ square meters These calculations give the volume of water the tank can hold and the total outer surface area needed for construction.