Circumference = 2πr → 31.4 = 2 × 3.14 × r → r = 31.4 / 6.28 = 5 m

Wed, 06 May 2026 03:35:50 +0000

How to Calculate the Radius from Circumference: A Simple Guide Using π Understanding the relationship between circumference and radius is fundamental in geometry and everyday applications — from engineering to architecture. The formula Circumference = 2πr is a cornerstone in circular measurements, and knowing how to rearrange it helps solve real-world problems quickly and accurately. ### The Basic Formula
The circumference (C) of a circle is calculated using:
C = 2πr
where:
- C = circumference
- r = radius
- π (pi) ≈ 3.14 (a mathematical constant representing the ratio of a circle’s circumference to its diameter) For instance, if the circumference is 31.4 meters, we can find the radius using this formula.