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 r is the radius of the circle and π (pi) is a mathematical constant approximately equal to 3.14159.

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 formula shows that circumference is directly proportional to the radius, with 2π being the constant of proportionality.

3. Importance of Circumference Calculation

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

4. Using the Calculator

Tips: Enter the radius in any length unit (meters, inches, 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 radius and diameter?
A: The radius is half the diameter. The formula can also be written as C = πd where d is diameter.

Q2: What's 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: Can I use this for semi-circles?
A: For a semi-circle, calculate full circumference then divide by 2 and add the diameter.

Q4: How accurate is this calculation?
A: The calculation is mathematically exact. Accuracy depends on the precision of your radius measurement.

Q5: What are some practical applications?
A: Wheel revolutions, circular fencing, satellite orbits, and any situation involving circular measurements.