1. **Find the circumference of a circle with diameter 5.9 ft.** The formula for circumference is $$C = \pi d$$ where $d$ is the diameter. Using $\pi = 3.14$ (since 5.9 is not divisible by 7, 3.14 is simpler): $$C = 3.14 \times 5.9 = 18.526$$ Rounded to the nearest hundredth: $$C \approx 18.53 \text{ ft}$$ 2. **Find the circumference of a circle with diameter 56 cm.** Since 56 is divisible by 7, use $\pi = \frac{22}{7}$ for exact fraction: $$C = \frac{22}{7} \times 56$$ Simplify: $$C = \frac{22}{\cancel{7}} \times \cancel{7} \times 8 = 22 \times 8 = 176$$ So, $$C = 176 \text{ cm}$$ 3. **Find the circumference of a circle with diameter 35 in.** Since 35 is divisible by 7, use $\pi = \frac{22}{7}$: $$C = \frac{22}{7} \times 35$$ Simplify: $$C = \frac{22}{\cancel{7}} \times \cancel{7} \times 5 = 22 \times 5 = 110$$ So, $$C = 110 \text{ in}$$ 4. **For which problems did you use $\frac{22}{7}$ for $\pi$? Explain your choice.** Used $\frac{22}{7}$ for problems 12 and 13 because their diameters (56 and 35) are divisible by 7, making the fraction exact and easier to calculate. Used 3.14 for problem 11 because 5.9 is not divisible by 7, so decimal approximation is simpler. 5. **A circular fountain has a radius of 9.4 feet. Find its diameter and circumference to the nearest hundredth.** Diameter formula: $$d = 2r = 2 \times 9.4 = 18.8 \text{ ft}$$ Circumference formula: $$C = \pi d = 3.14 \times 18.8 = 59.032$$ Rounded: $$C \approx 59.03 \text{ ft}$$ 6. **Find the radius and circumference of a CD with diameter 4.75 inches.** Radius: $$r = \frac{d}{2} = \frac{4.75}{2} = 2.375 \text{ in}$$ Circumference: $$C = \pi d = 3.14 \times 4.75 = 14.915$$ Rounded: $$C \approx 14.92 \text{ in}$$