Circle Calculator

Radius:
Diameter:
Circumference:
Area:
Decimal places:
Circle Diagram
Radius Diameter Circumference Area indicator Circle Properties Radius (r): 0 Diameter (d = 2r): 0 Circumference (C = 2πr): 0 Area (A = πr²): 0 • d = 2r • C = 2πr = πd • A = πr²

Circle Calculator

What is a Circle?

A circle is a two-dimensional shape with all points equidistant from a central point called the center. The distance from the center to any point on the circle is called the radius.

Formulas for Circles

Let \(r\) be the radius, \(d\) be the diameter, \(C\) be the circumference, and \(A\) be the area. Then:

  1. Radius: \(r = \frac{d}{2}\)
  2. Diameter: \(d = 2r\)
  3. Circumference: \(C = 2\pi r\)
  4. Area: \(A = \pi r^2\)

Step-by-Step Calculations

Let's calculate these properties for a circle with radius \(r = 5\) units:

  1. Radius: \[r = 5 \text{ units}\]
  2. Diameter: \[d = 2 \times r = 10 \text{ units}\]
  3. Circumference: \[C = 2 \times \pi \times r = 31.42 \text{ units}\]
  4. Area: \[A = \pi \times r^2 = 78.54 \text{ square units}\]

Visual Representation

Radius = 5 units Diameter = 10 units Center Calculations: 1. Radius (r) = 5 2. Diameter = 2r = 10 3. C = 2πr = 31.42 4. A = πr² = 78.54 Legend: Radius Diameter Circumference = 31.42 units Area = 78.54 sq units

This diagram illustrates the circle with the calculated dimensions and properties.