1. **Problem Statement:** Find the circumference of each circle using the given values and the specified value of $\pi$. 2. **Formula:** The circumference $C$ of a circle is given by: $$C = 2 \pi r = \pi d$$ where $r$ is the radius and $d$ is the diameter. 3. **Important rules:** - If diameter $d$ is given, use $C = \pi d$. - If radius $r$ is given, use $C = 2 \pi r$. - Use $\pi = 3.14$ for problems in section I and III. - Use $\pi = \frac{22}{7}$ for problems in section II. --- ### Section I (Use $\pi = 3.14$): A. Diameter $d = 4$ cm $$C = 3.14 \times 4 = 12.56 \text{ cm}$$ B. Diameter $d = 90$ m $$C = 3.14 \times 90 = 282.6 \text{ m}$$ C. Diameter $d = 3$ ft $$C = 3.14 \times 3 = 9.42 \text{ ft}$$ D. Diameter $d = 2.1$ m $$C = 3.14 \times 2.1 = 6.594 \text{ m}$$ E. Diameter $d = 20$ ft $$C = 3.14 \times 20 = 62.8 \text{ ft}$$ F. Diameter $d = 3.8$ cm $$C = 3.14 \times 3.8 = 11.932 \text{ cm}$$ G. Radius $r = 250$ m $$C = 2 \times 3.14 \times 250 = 1570 \text{ m}$$ H. Radius $r = 5$ cm $$C = 2 \times 3.14 \times 5 = 31.4 \text{ cm}$$ --- ### Section II (Use $\pi = \frac{22}{7}$): I. Diameter $d = 14$ ft $$C = \frac{22}{7} \times 14 = 22 \times \cancel{2} = 44 \text{ ft}$$ J. Diameter $d = 28$ in $$C = \frac{22}{7} \times 28 = 22 \times \cancel{4} = 88 \text{ in}$$ K. Diameter $d = 49$ mm $$C = \frac{22}{7} \times 49 = 22 \times 7 = 154 \text{ mm}$$ L. Diameter $d = 10 \frac{1}{2} = \frac{21}{2}$ ft $$C = \frac{22}{7} \times \frac{21}{2} = \frac{22 \times 21}{7 \times 2} = \frac{462}{14} = 33 \text{ ft}$$ M. Radius $r = 21$ mm $$C = 2 \times \frac{22}{7} \times 21 = 2 \times 22 \times 3 = 132 \text{ mm}$$ N. Radius $r = 3 \frac{1}{2} = \frac{7}{2}$ in $$C = 2 \times \frac{22}{7} \times \frac{7}{2} = 22 \text{ in}$$ O. Radius $r = 105$ mm $$C = 2 \times \frac{22}{7} \times 105 = 2 \times 22 \times 15 = 660 \text{ mm}$$ P. Radius $r = \frac{3}{4}$ in $$C = 2 \times \frac{22}{7} \times \frac{3}{4} = \frac{33}{7} = 4 \frac{5}{7} \text{ in}$$ --- ### Section III (Use $\pi = 3.14$): Q. Diameter of bicycle wheel $d = 27$ in Distance traveled per turn = circumference $$C = 3.14 \times 27 = 84.78 \text{ in}$$ R. Minute hand length (radius) $r = 6$ ft Distance point moves in one hour = circumference of circle traced by hand $$C = 2 \times 3.14 \times 6 = 37.68 \text{ ft}$$ --- **Final answers:** A: 12.56 cm B: 282.6 m C: 9.42 ft D: 6.594 m E: 62.8 ft F: 11.932 cm G: 1570 m H: 31.4 cm I: 44 ft J: 88 in K: 154 mm L: 33 ft M: 132 mm N: 22 in O: 660 mm P: 4 5/7 in Q: 84.78 in R: 37.68 ft