Length of the fence of trapezium ABCD = AB + BC + CD + DA
120 m = AB + 48 m + 17 m + 40 m
AB = 120 m - 105 m = 15 m
Area of the field ABCD
= \(\frac{1}{2}\) × (AD + BC) × AB
= \(\frac{1}{2}\) × (40 + 48) × 15 m
= \(\frac{1}{2}\) × (88 m) × 15 m
= 44 m × 15 m
= 660 m²
Thus, area of the field ABCD is 660 m²