2 x pi x r (radius) or pi x d (diameter) equal circumference of a circle.
C=pi *d C=> circumference pi is about 3.141592 d=>diameter
the formula is 2*pi*r
Circumference of a circle is C=pi*diameter. This is the same as C=2*pi*radius, since the 2 doubles the radius so that it becomes the diameter.
Formula of Circumference of a circle: 3.14*Diameter of the circle.You could also do:3.14*3.14*radius.
Circumference is equal to pi X diameter
Learn about Circumference Applications
How to Calculate the Circumference of a Circle
How to Find Circumference
How to Apply the Circumference of a Circle to Problems