It depends on what information you have: radius, diameter, lengths of tangents from a point outside the circle, length of chord and its distance from the centre, etc. Also, the term is circumference, not circumfrence.
By multiplying the diameter by pi, since the circumference of a circle is 3.14 times the diameter.
The formula is circumference= pi times diameter. pi=3.1415926.
circumfrence off the circle
Circumfrence = pi * diameter It can be experimentally derived very easily.
divide
Circumfrence
the circumfrence of a circle is pi times it's radius squared.
Circumfrence
18.84
The circumference of a circle is (diameter) multiplied by (pi).
22*pi
pi times diameter
25.1
Pi times radius squared.
Circumfrence is the perimeter of a circle, the line that makes a circle looks like a circle Imagine a perfect circle drawn on a piece of paper. Take the length of the line of the circle (by line I mean the part that is actually drawn on the piece of paper the ring) and there, you have the circumfrence. The circumfrence is exactly π times the size of the diameter (if you don't know what those two things are ignore this)
The circumfrence; Pi (or 3.14) times the width across the circle :)