Calculate the area, circumference and diameter of Circle (Circle Calculator)  

where,
r = radius
π = 3.14
Properties of a Circle:
Center  A point inside the circle. All points on the circle are equidistant (same distance) from the center point.
Radius  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