1. What is a Circle Calculator?

A Circle Calculator is a tool that calculates the area and circumference of a circle based on its radius. These fundamental geometric properties are essential in various mathematical and real-world applications.

2. How Does the Calculator Work?

The calculator uses the standard circle formulas:

Where:

• \( r \) — Radius of the circle
• \( \pi \) — Mathematical constant (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 calculations are fundamental in geometry, engineering, architecture, and various scientific fields. They're used in designing circular objects, calculating material requirements, and solving spatial problems.

4. Using the Calculator

Tips: Enter the radius in feet. The radius must be a positive value. The calculator will automatically compute both area (in square feet) and circumference (in feet).

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, then enter that value.

Q2: Can I use different units?
A: Yes, but ensure all measurements use the same unit system. The results will be in square units for area and linear units for circumference.

Q3: How accurate are the calculations?
A: The calculations use the precise value of π available in PHP, providing highly accurate results.

Q4: What is the value of π used in calculations?
A: The calculator uses PHP's built-in M_PI constant, which provides π to available precision (typically about 15 decimal places).

Q5: Can I calculate sector area or arc length with this calculator?
A: This calculator only computes basic circle properties. For sector area or arc length, additional information (like angle) would be needed.