1. **Problem statement:** Find the area and circumference of circles with given radius or diameter. 2. **Formulas:** - Area of a circle: $$A = \pi r^2$$ - Circumference of a circle: $$C = 2 \pi r$$ - Diameter and radius relation: $$d = 2r$$ 3. **Calculations:** **1. radius = 9 m** $$A = \pi \times 9^2 = 81\pi \approx 254.5$$ $$C = 2 \pi \times 9 = 18\pi \approx 56.5$$ **2. diameter = 14 cm** $$r = \frac{14}{2} = 7$$ $$A = \pi \times 7^2 = 49\pi \approx 153.9$$ $$C = 2 \pi \times 7 = 14\pi \approx 43.98$$ **3. radius = 3.78 ft** $$A = \pi \times 3.78^2 = \pi \times 14.2884 \approx 44.9$$ $$C = 2 \pi \times 3.78 = 7.56\pi \approx 23.7$$ **4. diameter = 25 m** $$r = \frac{25}{2} = 12.5$$ $$A = \pi \times 12.5^2 = 156.25\pi \approx 490.9$$ $$C = 2 \pi \times 12.5 = 25\pi \approx 78.5$$ **5. radius = 18 in** $$A = \pi \times 18^2 = 324\pi \approx 1017.9$$ $$C = 2 \pi \times 18 = 36\pi \approx 113.1$$ **6. radius = 5 cm** $$A = \pi \times 5^2 = 25\pi \approx 78.5$$ $$C = 2 \pi \times 5 = 10\pi \approx 31.4$$ **7. radius = 4.5 in** $$A = \pi \times 4.5^2 = 20.25\pi \approx 63.6$$ $$C = 2 \pi \times 4.5 = 9\pi \approx 28.3$$ **8. radius = 8.9 cm** $$A = \pi \times 8.9^2 = 79.21\pi \approx 248.8$$ $$C = 2 \pi \times 8.9 = 17.8\pi \approx 55.9$$ **9. Area of shaded annulus with outer radius 15 and inner radius 7:** $$A = \pi R^2 - \pi r^2 = \pi (15^2 - 7^2) = \pi (225 - 49) = 176\pi \approx 552.9$$ **10. Area of shaded region: square with side 10 cm and inscribed circle** - Area of square: $$10^2 = 100$$ - Radius of inscribed circle: $$r = \frac{10}{2} = 5$$ - Area of circle: $$\pi \times 5^2 = 25\pi \approx 78.5$$ - Shaded area = square area - circle area = $$100 - 78.5 = 21.5$$ **Final answers rounded to one decimal place:** 1. A = 254.5, C = 56.5 2. A = 153.9, C = 44.0 3. A = 44.9, C = 23.7 4. A = 490.9, C = 78.5 5. A = 1017.9, C = 113.1 6. A = 78.5, C = 31.4 7. A = 63.6, C = 28.3 8. A = 248.8, C = 55.9 9. A = 552.9 10. A = 21.5