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3) A surveyor wants to find the area of a triangular field. She finds the angle between them to be 0=30", with a possible error of 0.9" . She measures the two sides of the field adjacent to O to be a = 500 ft and b = 720 ft, with a possible error of = foot in each measurement. The field is triangular so its area is given by A = - absino. Use 2 differentials to approximate the maximum resulting error in computing the area of the field. (6 pts)