# Calculate the area, circumference and diameter of Circle (Circle Calculator) A Circle is a set of points that is formed in a closed loop, every point on which is a fixed distance from a center point. The radius of a circle is the distance from the center of a circle to any point on the circle. The distance across a circle through the center is called the diameter.
Calculate the area, circumference and diameter of Circle (Circle Calculator)
 Radius: Diameter of Circle( 2r ): Area of Circle (πr² ): Circumference of Circle( 2πr): Angle : Result Area (½×arc×(angle in degree) )
Formula
Area of Circle = πr²
Diameter of Circle = 2r
Circumference of Circle = 2πr = πd
Area of Sector = πr² (θ/360) = ½ *arc * (angle in degree)

where,
π = 3.14

A circle is a round plane figure whose boundary or the circumference consists of points equidistant from a fixed center.

Properties of a Circle:
Center   -
A point inside the circle. All points on the circle are equidistant (same distance) from the center point.
The radius is the distance from the center to any point on the circle. It is half the diameter. See Radius of a circle. Diameter - The distance across the circle. The length of any chord passing through the center. It is twice the radius. See Diameter of a circle.
Circumference
- The circumference is the distance around the circle.

Examples: Find the area, diameter and circumference of a circle with the given radius 4.
Step 1: Find the area.
Area = πr² = 3.14 * 4² = 3.14 * 16 = 50.24

Step 2: Find the diameter.
Diameter = 2r = 2 *4 = 8

Step 3: Find the circumference.
Circumference = πd = 3.14 *8 = 25.12

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