Final answer:
The circumference of a circle can be expressed as 2πr.
Step-by-step explanation:
The circumference of a circle can be expressed in terms of its radius (r) by the formula C = 2πr, where C represents the circumference. This formula tells us that the circumference is equal to the product of 2π and the radius of the circle. For example, if the radius of a circle is 5 units, the circumference would be 2π(5) = 10π units.