The figure is composed of 2 shapes. A rectangle and a right triangle.
Area of the Rectangle = 600 ft * 200 ft = 120,000 ft²
Area of the right triangle = (600 ft * 450 ft)/2 = 270,000 / 2 = 135,000 ft²
Total area = 120,000 ft² + 135,000 ft² = 260,000 ft²
Area of the house = 45 ft * 38 ft = 1,710 ft²
Area of the woods = 118 ft * 60 ft = 7,080 ft²
Area of the front yard = 78 ft * 40 ft = 3,120 ft²
Area of farmed land = 260,000 - 1,710 - 7,080 - 3,120 = 248,090 ft²
248,090 ft² * 1acre/43,560 ft² = 5.695 acres