1. What is Circle Calculator?

The Circle Calculator computes the area and circumference of a circle using the radius. These fundamental geometric calculations are essential in mathematics, engineering, and various scientific applications.

2. How Does the Calculator Work?

The calculator uses these fundamental circle formulas:

Where:

• \( A \) — Area (square length units)
• \( C \) — Circumference (length units)
• \( r \) — Radius (length units)
• \( \pi \) — Pi (approximately 3.14159)

Explanation: The area represents the space enclosed by the circle, while the circumference is the distance around the circle.

3. Importance of Circle Calculations

Details: Circle properties are fundamental in geometry and have practical applications in engineering, physics, architecture, and many real-world scenarios involving circular objects.

4. Using the Calculator

Tips: Enter the radius in any consistent length unit. The results will be in corresponding square units for area and linear units for circumference.

5. Frequently Asked Questions (FAQ)

Q1: What if I know the diameter instead of radius?
A: Simply divide the diameter by 2 to get the radius before entering it into the calculator.

Q2: How precise are the calculations?
A: The calculator uses PHP's built-in M_PI constant (approximately 3.1415926535898) for high precision.

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

Q4: What units should I use?
A: Any consistent unit can be used (meters, inches, feet, etc.), just be sure to interpret the results in the same unit system.

Q5: Why do we use π in these formulas?
A: π (pi) is the fundamental constant representing the ratio of a circle's circumference to its diameter, appearing in all circle calculations.