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Circle calculator

Area, circumference and diameter of a circle from its radius or diameter.

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Area 78.5398

How it works

A = π × r² · C = 2 × π × r

The radius is the distance from the center to the edge; the diameter is twice that. Area is π × r², and the circumference (the distance around) is 2 × π × r, or π × d. π is about 3.14159. Any unit works; the area comes out in that unit squared.

  1. Area = π × r² 3.14159265 × 5² = 78.5398
  2. Circumference = 2 × π × r 2 × 3.14159265 × 5 = 31.4159

Printed from rocketcalc.io/geometry/circle