Question 1160208
Quarter pounder's area:
Just one surface, like either upper OR lower
{{{pi*(4/2)^2=4pi}}}


Half-Pounder is double the area of quarter-pounder.
{{{8pi=pi*(d/2)^2}}}, d for diameter;

{{{8pi=pi(1/4)d^2}}}

{{{8*4=d^2}}}

{{{d=sqrt(2^5)}}}

{{{highlight(d=4sqrt(2))}}}