1. What is Circle Area?

The area of a circle is the space contained within its circumference. It's measured in square units (square feet in this calculator) and is fundamental in geometry and real-world applications like construction and landscaping.

2. How Does the Calculator Work?

The calculator uses the circle area formula:

Where:

• \( \pi \) — Mathematical constant (~3.14159)
• \( r \) — Radius of the circle (distance from center to edge)

Explanation: The area grows with the square of the radius - doubling the radius makes the area four times larger.

3. Importance of Circle Area Calculation

Details: Calculating circle area is essential in many fields including architecture (circular rooms, pools), landscaping (circular gardens), and engineering (pipe cross-sections).

4. Using the Calculator

Tips: Simply enter the radius in feet. The radius must be a positive number. The calculator will compute the area in square feet.

5. Frequently Asked Questions (FAQ)

Q1: What if I know the diameter instead of radius?
A: Divide the diameter by 2 to get the radius before using the calculator.

Q2: Can I use this for other units besides feet?
A: The calculator specifically calculates square feet. For other units, convert your measurement to feet first.

Q3: How accurate is the calculation?
A: The calculation uses PHP's built-in M_PI constant (approximately 3.1415926535898) for high precision.

Q4: What's the largest circle this can calculate?
A: Theoretically unlimited, but practical limits depend on your computer's number handling capabilities.

Q5: Can this calculate partial circles (sectors)?
A: No, this calculates full circle area only. For sectors, you'd need to know the angle of the sector.