2r
Why?
- The diameter, or the distance across a circle that passes through the center of the circle is 2R (twice the radius). The circumference, or distance around a circle is 2 R. The area enclosed by a circle is R. 2. Note that =3.1415926535...
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If you know the radius:
The diameter can be calculated using the formula. Diameter = 2R or d = 2 x radius. R is for the radius of the circle.
