1. What is the Circumference Formula?

The circumference of a circle is the linear distance around its edge. The formula relates the circumference (C) to the radius (r) of the circle using the mathematical constant π (pi).

2. How Does the Calculator Work?

The calculator uses the circumference formula:

Where:

• \( C \) — Circumference (length units)
• \( r \) — Radius (length units)
• \( \pi \) — Mathematical constant (~3.14159)

Explanation: The circumference is simply 2 times π times the radius of the circle.

3. Importance of Circumference Calculation

Details: Calculating circumference is fundamental in geometry, engineering, and various real-world applications like wheel design, circular construction, and more.

4. Using the Calculator

Tips: Enter the radius in any length unit (must be positive). The result will be in the same units as the input.

5. Frequently Asked Questions (FAQ)

Q1: What if I know the diameter instead of radius?
A: The radius is half the diameter. You can divide your diameter by 2 before entering it.

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

Q3: Can I use negative values for radius?
A: No, radius must be a positive number as physical distances can't be negative.

Q4: How precise are the results?
A: Results are rounded to 2 decimal places for readability while maintaining practical accuracy.

Q5: What units should I use?
A: Any consistent length unit can be used (meters, inches, feet, etc.) as long as input and output use the same units.