Print Friendly, PDF & Email
Parts of a circle

The geometry of a circle

The area of a circle is the flat surface inside its circumference. The area is always equal to the radius squared, multiplied by π (pi).

Here’s a proof that this is always true for any circle.

Learn by doing: figure out the area of some circles around you.
Radius
Diameter
Circumference of a Circle
More about Geometry

Bibliography and further reading about circles:

  

More about Geometry
More about Math
Quatr.us home