1. What is Diameter?

The diameter of a circle is the longest distance from one edge of the circle to the opposite edge, passing through the center point. It is twice the length of the radius.

2. How to Calculate Diameter

The diameter can be calculated using the simple formula:

Where:

• \( D \) — Diameter of the circle
• \( r \) — Radius of the circle

Explanation: Since the radius is the distance from the center to any point on the circle, the diameter is simply two radii placed end-to-end through the center.

3. Practical Applications

Details: Knowing the diameter is essential in many real-world applications like construction (determining pipe sizes), engineering (calculating wheel rotations), and everyday measurements (determining circular object sizes).

4. Using the Calculator

Tips: Simply enter the radius of your circle in any units (inches, centimeters, meters, etc.). The calculator will automatically compute the diameter in the same units.

5. Frequently Asked Questions (FAQ)

Q1: Can I calculate diameter if I know circumference?
A: Yes, diameter = circumference / π (approximately 3.14159).

Q2: What's the difference between diameter and radius?
A: Radius is half the diameter - it's the distance from center to edge, while diameter spans the whole circle through the center.

Q3: How precise should my radius measurement be?
A: For most practical purposes, measuring to the nearest millimeter or 1/16th inch is sufficient.

Q4: Can this formula be used for spheres?
A: Yes, the same diameter formula applies to perfect spheres as well as circles.

Q5: What if I only know the area of the circle?
A: You can find radius from area (r = √(A/π)), then calculate diameter from radius.