Length of the fence of a trapezium shaped field ABCD is 120 m.

If a perpendicular from D to BC is drawn then it will be equal to AB,

then EC = 48-40 = 8 m.

In ΔDEC DE² = DC²-EC²

DE² = 17² - 8² = 289 - 64 = 225

Or, DE = 15 m

Area of Trapezium = 1/2 × (sum of parallel sides) × height

= 1/2 × (48 + 40) × 15

= 660 m²