tentukan panjang DG dan HF

++misal DG = x, maka DE= 4 + x
EF : GH = ED : GD
12 : 8 = (4+x) ; x
12x = 8 (4+x)
12x = 32 + 8
12x -8x = 32
4x = 32
x = 8
misal HF = y, maka DF = 8 + y
EF : GH = DF : HF
12 : 8 = (8+y) : 8
12.8 = 8(8+y)
96 = 64 +8y
8y = 32
y = 4