2-d shape, rim length=21, area=13
area/leng=0.6190476
first tri serkel...it hav the biggest area/length av NE shape
area=pi*r*r
rim length=2pi*r
area/rim length=r/2
serkel area=pi*r*r =13, so r*r=13/pi=4.13802859
r=root(4.1....)=2.0342145
area/length=2.0342145/2=1.017107
Yer data is smaller than this, so it is possabel (legal
It kan be NE shape, but not a serkel