Final answer:
The total area of Marty's rectangular-shaped backyard, which measures 43.2 feet in width and 32.1 feet in length, is calculated as 1385.92 square feet.
Step-by-step explanation:
The question asks us to calculate the total area of a rectangular backyard with a given width and length. To find the area of a rectangle, you multiply the width by the length. Using this formula, we can calculate Marty's backyard area: Area = width × length. The width of Marty's backyard is 43.2 feet and the length is 32.1 feet, therefore, Area = 43.2 ft × 32.1 ft = 1385.92 square feet. This matches answer choice a) 1385.92 square feet