1. What is the Circle Area Formula?

The area of a circle is calculated using the formula π × r², where π (pi) is approximately 3.14159 and r is the radius of the circle. This formula gives the area in square units, which in this case is square feet.

2. How Does the Calculator Work?

The calculator uses the circle area formula:

Where:

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

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

3. Importance of Circle Area Calculation

Details: Calculating the area of a circle is essential in various fields including construction, landscaping, manufacturing, and any application requiring measurement of circular spaces.

4. Using the Calculator

Tips: Enter the radius of the circle in feet. The radius must be a positive value greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What if I know the diameter instead of the radius?
A: The radius is half the diameter. If you know the diameter, divide it by 2 to get the radius before using the calculator.

Q2: How accurate is the π value used in calculations?
A: The calculator uses PHP's built-in M_PI constant which provides π with approximately 14 decimal places of precision.

Q3: Can I use this for metric measurements?
A: This calculator is specifically designed for square feet. For metric measurements, you would need to convert to square meters instead.

Q4: What are common applications of circle area calculations?
A: Common applications include calculating flooring for circular rooms, determining paint needed for circular surfaces, planning circular gardens, and various engineering applications.

Q5: Why is the result in square feet?
A: Because the radius is input in feet, the area calculation naturally results in square feet, which is the standard unit for area measurement in the imperial system.