Answer:d. 0.771.Step-by-step explanation:This probability is equal to the area other than the green triangle divided by the total area of backyard.Total area = 120^2 = 14400Area of green triangle = 1/2 * 120 * 55 = 3300So area of the part of yard not covered by the triangle = 14400 - 3300and the required probability = Β (14400 - 3300) / 14400= 0.771.