Geometry

Circumference of a Circle

Formula

C = 2 × π × r

What is Circumference of a Circle?

The circumference is the total distance around the boundary of a circle. It is calculated by multiplying 2, pi, and the radius.

Variables

C
C — Circumference
r
r — Radius of the circle
π
π — Pi (approximately 3.14159)

Worked Examples

Example 1

Find the circumference of a circle with radius 10 cm.

Solution:

C = 2 × π × 10 = 20π ≈ 62.83 cm

Frequently Asked Questions

Related Formulas

Area of a Circle

A = π × r²

Area of a Rectangle

A = l × w

Area of a Triangle

A = ½ × b × h

Pythagorean Theorem

a² + b² = c²

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