ABCD dreptunghi
AC , BD diag.=12
ungh.COB si DOA=60 grade⇒ung.DOC si AOB=120
AO=OC=AC/2=6
DO=OB=DB/2=6
in ΔCOB
CO≡OB
ung. COB=60 ⇒ΔCOB=echilateral⇒CB=AD=6=ΔABC dr inB
⇒T.P= CD^2+AB^2=AC^2=>36+AB^2=144=>AB=6√3.
=>.P=2(L+l)
P=2(6√3+6)
P=12√3+12
P=12(√3+1)
