1. What is the Circumference Formula?

The circumference of a circle is the linear distance around its edge. It's calculated using the formula C = 2πr, where C is circumference, π is the mathematical constant pi (approximately 3.14159), and r is the radius of the circle.

2. How Does the Calculator Work?

The calculator uses the circumference formula:

Where:

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

Explanation: The formula multiplies the radius by 2 and by π to calculate the total distance around the circle.

3. Importance of Circumference Calculation

Details: Calculating circumference is fundamental in geometry, engineering, and various practical applications like wheel rotation calculations, circular construction projects, and more.

4. Using the Calculator

Tips: Enter the radius in any length unit (meters, inches, feet, etc.). The result will be in the same units. The radius must be a positive number.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between circumference and perimeter?
A: Circumference is specifically the perimeter of a circle, while perimeter refers to the total distance around any closed shape.

Q2: Can I calculate circumference from diameter?
A: Yes, the formula becomes C = πd where d is diameter (d = 2r).

Q3: What is the value of pi used in calculations?
A: The calculator uses PHP's built-in pi() function which provides π to available precision (about 15 digits).

Q4: What units should I use?
A: Any consistent length units can be used (meters, inches, cm, etc.). The result will be in the same units as the radius.

Q5: How accurate is the calculation?
A: The calculation is mathematically precise based on the input radius value and PHP's implementation of π.