Ето още една идея :
Нека [tex]S_{DPM } =x ,S_{MEA } =a ,S_{NBF } =b ,S_{QCN } =c , S _{BCN }=y=?[/tex]
[tex]S_{ABC } +S_{ACD } =S_{ABD } +S_{BCD }[/tex]
3(b+y)+3(x+154)=3(a+154)+3(c+y) ; c=b+x-a
(1) 
[tex]S_{ABCD } = S_{DPEA } +S_{QCBF } +S_{PQE } +S_{EFQ }[/tex]
[tex]S_{ABCD }[/tex]= (154+112+a+x) +(99+y+b+c) +x+112+b+99
[tex]S_{ABCD }[/tex]=576+a+2b+c+2x+y
(2) зам. (1) в (2)
[tex]S_{ABCD }[/tex]=576+a+2b+b+x-a+2x+y
[tex]S_{ABCD }[/tex]=576+3b+3x+y
(3)[tex]S_{ABCD } =S_{ACD } +S_{ABC }[/tex]
[tex]S_{ABCD }[/tex]=3x+462+3b+3y
(4)От (3) и (4) [tex]\Rightarrow[/tex] 3x+462+3b+3y=576+3b+3x+y
y= [tex]\frac{114}{2}[/tex]= 57