1. What is Circumference?

The circumference is the length around a circle. It's the perimeter of a circle, calculated using the radius or diameter of the circle.

2. How Does the Calculator Work?

The calculator uses the circumference formula:

Where:

• \( C \) — Circumference (length units)
• \( r \) — Radius of the circle (length units)
• \( \pi \) — Mathematical constant (approximately 3.14159)

Explanation: The circumference is directly proportional to the radius, with 2π being the constant of proportionality.

3. Importance of Circumference Calculation

Details: Calculating circumference is essential in many real-world applications like construction, engineering, manufacturing, and any field that deals with circular objects.

4. Using the Calculator

Tips: Enter the radius of the circle in any length units. The result will be in the same units. The radius must be a positive number.

5. Frequently Asked Questions (FAQ)

Q1: Can I use diameter instead of radius?
A: Yes, the formula can also be written as \( C = \pi d \) where d is diameter. Just divide diameter by 2 to get radius.

Q2: What is the value of π used in calculations?
A: The calculator uses PHP's built-in pi() function which provides π to about 14 decimal places (3.1415926535898).

Q3: How accurate is this calculation?
A: The calculation is mathematically exact. Accuracy depends on the precision of your radius measurement.

Q4: Can I calculate radius from circumference?
A: Yes, the formula can be rearranged: \( r = C / (2 \pi) \).

Q5: What units should I use?
A: Any length units can be used (meters, inches, feet, etc.), just be consistent. The result will be in the same units as your input.