1. What is the Circle Area Formula?

The circle area formula calculates the square footage of a circle from its radius. It is one of the fundamental geometric formulas used in mathematics, construction, and design.

2. How Does the Calculator Work?

The calculator uses the circle area formula:

Where:

• \( SF \) — Square footage (square feet)
• \( \pi \) — Mathematical constant (approximately 3.14159)
• \( r \) — Radius of the circle (feet)

Explanation: The formula calculates the area enclosed by a circle by multiplying the mathematical constant π (pi) by the square of the circle's radius.

3. Importance of Circle Area Calculation

Details: Calculating the area of circles is essential in various fields including construction, landscaping, manufacturing, and interior design. It helps determine material requirements, space planning, and cost estimation for circular surfaces.

4. Using the Calculator

Tips: Enter the radius of the circle in feet. The value must be positive and valid. The calculator will compute the square footage using the standard circle area formula.

5. Frequently Asked Questions (FAQ)

Q1: What if I have the diameter instead of the radius?
A: Divide the diameter by 2 to get the radius, then use that value in the calculator.

Q2: How accurate is the calculation?
A: The calculation uses the precise value of π (pi) and provides results accurate to two decimal places.

Q3: Can I use different units of measurement?
A: This calculator is designed for feet, but you can convert other units to feet before calculation.

Q4: What is the value of π used in this calculator?
A: The calculator uses PHP's built-in M_PI constant, which is accurate to approximately 14 decimal places.

Q5: Can this calculator be used for partial circles?
A: No, this calculator is designed for full circles. For partial circles (sectors), additional calculations are needed.