1. What is Semi Circle Perimeter?

The perimeter of a semi-circle is the total length around the semi-circular shape, which includes both the half-circumference and the diameter. It's important in various geometry and real-world applications.

2. How Does the Calculator Work?

The calculator uses the semi-circle perimeter formula:

Where:

• \( P \) — Perimeter (length units)
• \( \pi \) — Mathematical constant pi (~3.14159)
• \( r \) — Radius of the semi-circle (length units)

Explanation: The formula combines half the circumference of a full circle (\( \pi r \)) plus the diameter (\( 2r \)) to get the total perimeter.

3. Importance of Perimeter Calculation

Details: Calculating the perimeter of semi-circles is essential in architecture, engineering, and design where semi-circular shapes are used in structures, windows, arches, and other elements.

4. Using the Calculator

Tips: Enter the radius of your semi-circle. The value must be positive. The calculator will compute the perimeter including both the curved part and the straight diameter.

5. Frequently Asked Questions (FAQ)

Q1: Is this the same as half the circumference of a circle?
A: No, the perimeter of a semi-circle includes both the half-circumference AND the diameter.

Q2: What units should I use?
A: Use any consistent length unit (meters, feet, inches, etc.) for both input and output.

Q3: Can I use diameter instead of radius?
A: You would need to convert diameter to radius first (radius = diameter/2) before using this calculator.

Q4: How accurate is the calculation?
A: The calculation uses PHP's built-in M_PI constant (approximately 3.1415926535898) for high precision.

Q5: What if I only want the curved part?
A: For just the half-circumference (without the diameter), use \( \pi r \) instead of the full perimeter formula.