Respuesta :

dalendrk
r - the radius of the circle

C - the circumference of the circle

[tex]C=2\pi r[/tex]

The ratio:
[tex]\dfrac{r}{C}=\dfrac{r}{2\pi r}=\dfrac{1}{2\pi}\to\fbox{A.}[/tex]
circumference of a circle =2pie r 
if we find ratio then circumfernce:radius
by putting value

=r:2pie r
=
r/2pir
=1/2pie