Question 1043873
just substitute and see

{{{C=2pi*r}}}
{{{A=pi*r^2}}}
only  B give whole number area of circle.

{{{2*sqrt(pi)=2pi*r}}}
{{{2*sqrt(pi)/(2*pi)}}}={{{r}}}
square both sides
{{{4*(pi)/(4*(pi)^2)}}}={{{r^2}}}

area is {{{A=pi*r^2}}}
{{{pi}}}{{{4*(pi)/(4*(pi)^2)}}}={{{Area of circle}}}

which gives A={{{1}}} whole number area of circle,do for the rest.

A gives area of {{{9/4}}}

B gives area of {{{1}}}

C gives area of {{{1/(pi)}}


D gives area of {{{pi}}}


E gives {{{pi/2}}}

comment is welcome