Serkel area=pi*rad*rad
tabel diameter=4 ft, so radius=2 ft or 24 inch
Area=4*pi=4*3.14159265
tabel area=12.5663706 ft^2
4 mats=serkels with diameter=6 inch, so radius=3 inch=(1/4) ft
mat area=4*pi*(1/4)*(1/4)
=0.25*pi=0.785398162
tabel area - mat area=11.78097244