of a circle is
I want to calculate
 Area Circumference Radius Diameter All

A circle has circumference = 9

Calculate Area, Circumference, Radius, Diameter

C = 2πr

##### Rearranging the equation, we get:

 r  = C 2π

 r  = 9 2 * 3.1415926535898

 r  = 9 6.28319

r = 1.4323944878271

##### Calculate diameter (d):

d = 2r

d = 2 * 1.4323944878271

d = 2.8647889756541

##### Calculate Area (A):

A = πr2

A = π * 1.43239448782712

A = 2.0518π or 6.4459

r = 1.4323944878271
d = 2.8647889756541
A = 2.0518π or 6.4459

##### What is the Answer?
r = 1.4323944878271
d = 2.8647889756541
A = 2.0518π or 6.4459
##### How does the Circles Calculator work?
Free Circles Calculator - Calculates and solves for Radius, Diameter, Circumference, and Area of a Circle.
This calculator has 1 input.

### What 3 formulas are used for the Circles Calculator?

d=2r
A = 2πr2
C=2πr

For more math formulas, check out our Formula Dossier

### What 7 concepts are covered in the Circles Calculator?

area
Number of square units covering the shape
circle
the set of all points in the plane that are a fixed distance from a fixed point
circles
circumference
the perimeter of a circle or ellips
diameter
distance from two endpoints of a circle through the center
d = 2r
origin
On a two digit coordinate plane, the point (0, 0), where the x-axis and y-axis cross.