Circumference = 2πr = 31.4, so r = 31.4 / (2π) ≈ 5 cm.

["How to Calculate the Radius from Circumference: A Simple Guide (Using Circumference = 2πr = 31.4 cm)", "Understanding the relationship between a circle’s circumference and radius is essential for solving practical geometry problems. If you’ve ever wondered how to find the radius when you know the circumference, this guide breaks it all down clearly and simply — especially focusing on the formula:\nCircumference = 2πr = 31.4 cm, and how to calculate the radius as r = 31.4 / (2π) ≈ 5 cm.", "---", "### What Is Circumference?", "The circumference is the total distance around the edge of a circle. In standard formulas, it’s defined as:\nC = 2πr\nwhere:\n- C = circumference\n- r = radius\n- π (pi) ≈ 3.1416 (a constant representing the ratio of a circle’s circumference to its diameter)", "---", "### Given: Circumference = 31.4 cm", "We start with the equation:\nC = 2πr = 31.4 cm", "To find the radius ( r ), we rearrange the formula:\n[\nr = \frac{C}{2\pi}\n]", "Substitute the known value:\n[\nr = \frac{31.4}{2\pi}\n]", "Using π ≈ 3.1416, we calculate:\n[\nr = \frac{31.4}{2 \ imes 3.1416} = \frac{31.4}{6.2832} ≈ 5 \ ext{ cm}\n]", "---", "### Why r ≈ 5 cm When Circumference = 31.4 cm?", "A quick mental check helps confirm:\nCompute 2π × 5 ≈ 2 × 3.1416 × 5 = 31.416, which rounds to 31.4 cm — matching the given value.", "So, a radius of 5 cm gives a circumference of exactly 31.4 cm under this precise approximation.", "---", "### Real-World Applications", "Knowing how to compute radius from circumference is useful in many fields:", "- Engineering: Designing round structures like tanks and pipes\n- Manufacturing: Checking wheel circumferences and belt lengths\n- Daily Life: Estimating tire sizes, circular flower beds, or jar diameters", "---", "### Final Calculation Summary", "1. Start with: C = 2πr = 31.4 cm\n2. Solve for r:\n [\n r = \frac{31.4}{2\pi}\n ]\n3. Plug in π ≈ 3.1416:\n [\n r ≈ \frac{31.4}{6.2832} ≈ 5 \ ext{ cm}\n ]", "---", "### Conclusion", "Calculating the radius from circumference is straightforward with the formula r = C / (2π). With a circumference of 31.4 cm, the radius is approximately 5 cm — a simple yet powerful result in geometry with wide-ranging practical uses. Whether you’re a student, hobbyist, or professional, mastering this calculation helps sharpen your understanding of circular measurements.", "---", "Keywords: circumference formula, calculate radius from circumference, 2πr = 31.4, find radius 5 cm, π calculator, circle geometry, radius calculation, 2πr = 31.4 cm, math tutorial", "Meta description: Learn how to calculate the radius from circumference using the formula C = 2πr = 31.4 cm — with examples showing that r ≈ 5 cm.", "---", "Need more geometry help? Check out related articles on circle properties, diameter vs radius, or real-world circle measurements!"]