∵ 四边形BCEG是平行四边形 EG = BC = AD
∴ DG = DE - GE = DE - BC = 18 - 8 = 10
AG = AD + DG = 8 + 10 = 18
ABFD(阴影部分)的面积 = 三角形ABG面积 - 三角形DFG面积 = 18 X 12 ÷ 2 - 40 = 108 - 40 = 68
∵ 四边形BCEG是平行四边形 EG = BC = AD
∴ DG = DE - GE = DE - BC = 18 - 8 = 10
AG = AD + DG = 8 + 10 = 18
ABFD(阴影部分)的面积 = 三角形ABG面积 - 三角形DFG面积 = 18 X 12 ÷ 2 - 40 = 108 - 40 = 68