The circumference is similar to the perimeter in that it is the total length needed to draw the circle.
We note the circumference as c.
c = 2πr
or
c = πd
This depends on whether or not you know the radius (r) or the diameter (d)
Let’s calculate one manually, for example.
If r = 6 cm, then the circumference is c = 2π(6) = 12π cm, if writing in terms of π. If you prefer a numerical value, the answer rounded to the nearest tenth is 37.7 cm.
Suppose you only know the diameter? If the diameter is 8 cm, then the circumference is c = π(8) = 8π or 25.1 cm, rounded to the nearest tenth.
