1. What is Circumference?

The circumference (periphery) of a circle is the distance around the circle. It's the circle's perimeter and can be 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 (~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 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 consistent length units (meters, inches, etc.). The result will be in the same units. Radius must be a positive number.

5. Frequently Asked Questions (FAQ)

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

Q2: Can I calculate circumference using diameter?
A: Yes, the formula becomes \( C = \pi d \) where \( d \) is the diameter (diameter = 2 × radius).

Q3: What's the value of π used in calculations?
A: The calculator uses the PHP pi() function which provides π to about 14 decimal places (~3.1415926535898).

Q4: What are some practical applications of circumference?
A: Wheel rotations, circular fencing, pipe measurements, sports track design, and many engineering applications.

Q5: How accurate is the calculation?
A: The accuracy depends on the precision of your radius measurement and the π constant used. The calculator provides results rounded to 2 decimal places.