By definition we have the relationship between the diameter of a circle and its radius is as follows: r = d / 2 where r: radio d: diameter Since the diameter of the circle is 4, then the radius will be given by r = (4) / 2 = 2 answer the radius of the circle is 2 units.
The formula for calculating the radius of a circle given its diameter is radius equals diameter divided by two. Using the information given of a circle with a diameter of four, the radius is four divided by two, or two.
