1. **State the problem:** Calculate the area of a circle given its radius or diameter. 2. **Formula used:** The area $A$ of a circle is given by the formula: $$A = \pi r^2$$ where $r$ is the radius of the circle. 3. **Important rules:** - The radius $r$ is half the diameter $d$, so $r = \frac{d}{2}$. - If the diameter is given, first find the radius before calculating the area. 4. **Example 1: Sandbox circle with radius 8 feet** Calculate the area: $$A = \pi r^2 = 3.14 \times 8^2 = 3.14 \times 64 = 200.96 \approx 201 \text{ ft}^2$$ 5. **Example 2: Water pitcher opening with diameter 12 cm** First find the radius: $$r = \frac{12}{2} = 6 \text{ cm}$$ Calculate the area: $$A = \pi r^2 = 3.14 \times 6^2 = 3.14 \times 36 = 113.04 \approx 113 \text{ cm}^2$$ 6. **Check the options for the pool area:** Given options are 113 cm$^2$, 226 cm$^2$, and 19 cm$^2$. If the pool diameter is 12 cm, the area is approximately 113 cm$^2$. **Final answer:** - Sandbox area: $201$ ft$^2$ - Water pitcher opening area: $113$ cm$^2$ - Correct pool area option: $113$ cm$^2$