en.wikipedia.org/wiki/Circumference

The circumference of a closed curve or circular object is the linear distance around its edge. The circumference of a ...

www.mathgoodies.com/lessons/vol2/circumference.html

Circumference of a circle is presented in this interactive lesson from Math Goodies. Learn circumference at your own pace.

www.khanacademy.org/math/basic-geo/basic-geo-area-and-perimeter/area-circumference-circle/v/circumference-from-area

Learn how to find the circumference, the distance around a circle, when given the area.

www.khanacademy.org/math/basic-geo/basic-geo-area-and-perimeter/area-circumference-circle/a/radius-diameter-circumference

Learn the relationship between the radius, diameter, and circumference of a circle.

www.mathplanet.com/education/pre-algebra/more-about-equation-and-inequalities/calculating-the-circumference-of-a-circle

The distance around a rectangle or a square is as you might remember called the perimeter. The distance around a circle on the other hand is called the ...

www.bbc.co.uk/schools/gcsebitesize/maths/geometry/circlesrev2.shtml

A secondary school revision resource for GCSE Maths about higher level shapes and circles.

www.wikihow.com/Calculate-the-Circumference-of-a-Circle

How to Calculate the Circumference of a Circle. Whether you're doing craft work, putting fencing around your hot tub, or just solving a math problem for school, ...

www.omnicalculator.com/math/circumference

Use the circumference calculator to find the area, circumference and diameter of a circle.