Free Online Calculator .net

Circle Formulas in terms of radius r: (Π = Pi)

• Calculate the surface area of a circle:
  • A = Π * r^2
• Calculate the circumference of a circle:
  • C = 2 * Π * r

Circle Calculations:

Use the following additional formulas along with the formulas above.

• Given the radius of a circle calculate the area and circumference
  Given r find A, C
  • use the formulas above
• Given the area of a circle calculate the radius and circumference
  Given A find r, C
  • r = √(A / Π)
  • C = 2 * Π * r
• Given the circumference of a circle calculate the radius and area
  Given C find r, A
  • r = C / 2Π
  • A = Π * r^2