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Circle Calculator

Circle Parameters

cm

Results

Radius
10.0 cm
Distance from center
Diameter
20.0 cm
Width across circle
Circumference
62.8 cm
Perimeter
Area
314.2 cm²
Space inside

Circle Visualization

Radius Diameter

Circle Calculation Information

About Circles

A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the center.

Radius

The radius is the distance from the center of the circle to any point on its circumference. It's half the diameter.

Diameter

The diameter is a straight line passing from side to side through the center of a circle. It's twice the radius.

Circumference

The circumference is the linear distance around the edge of a circle. It's calculated as 2πr or πd.

Circle Formulas

Diameter (d):

d = 2 × r

Circumference (C):

C = 2 × π × r = π × d

Area (A):

A = π × r²

Where: r = radius, d = diameter, π ≈ 3.14159