0
1/2 of the diameter
IMPOSSIBLE
circumference = 2*pi*radius
if circumference = 2*radius:
2*radius=2*pi*radius
2*radius/(2*radius)=2*pi*radius/(2*radius)
1=pi
pi= 1 therefore it is impossible to have a circumference that is twice that of the radius
Radius = 1/2 of diameter
The radius is 1/2 of the circumference.
area of a circle = pi * radius² = 1 radius = √(1/pi)
circumference = 2pi * radius = 2pi * √(1/pi) = 3.5449077