S(GEF)=EF*GH=8(H is the vertical foot of CD in G direction).
GDE = Germany * high.
S(GFC)=CF*GH
Because DE=EF=FC
So S(GDC)=24.
S(GDC)=CP*DG(P is the vertical foot from C to BD).
s(GBC)= CP * BG = 12(BG = 1/3BD,BG= 1/2BG)
S(BCD)=S(GDC)+S(GBC)=36
S(ABCD)=2S(BCD)=72