Y/6 what is the constant

Was the 12 of GF given??
The area ratio should be 1:4, so if l×w = area (a) of DEFG, then L×W = Area (A) of WXYZ.
Since 4:1 is 4×1, A = 4×a or 4a
Since GF is length (l) and is 12, we can say that 12w = a
12×4 = 48 for length of ZY (L), and WX is also 48, and to find W would be: 48W = A
48W = 4a, since A=4a
Not sure what else you want by the limited information given!