1. What is the Circle Area Formula?

The area of a circle is calculated using the formula A = π × r², where π (pi) is approximately 3.14159 and r is the radius of the circle. This formula calculates the square footage of a circular area.

2. How Does the Calculator Work?

The calculator uses the circle area formula:

Where:

• \( A \) — Area of the circle (square feet)
• \( \pi \) — Mathematical constant (approximately 3.14159)
• \( r \) — Radius of the circle (feet)

Explanation: The formula squares the radius and multiplies it by π to calculate the area of the circle.

3. Importance of Circle Area Calculation

Details: Calculating the area of circular spaces is essential in construction, landscaping, flooring installation, and many other applications where accurate measurements are required.

4. Using the Calculator

Tips: Enter the radius of the circle in feet. The value must be positive (radius > 0). The calculator will automatically compute the area in square feet.

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?
A: This calculator works specifically with feet for radius and square feet for area. 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 about 14 decimal places (3.1415926535898).

Q5: Why would I need to calculate the area of a circle?
A: Circle area calculations are used in many practical applications including determining material needs for circular projects, calculating irrigation coverage, planning circular garden beds, and many construction applications.