S = 1/2 * a^2 = 8
a^2 = 16
a=4
L=2ПR
R=c/2
c^2= 2*a^2= 32
c=2<span>sqrt{2}</span>
<span>R=sqrt{2}</span>
АВ/ВС=4/9, притом AB=CD, BC=AD