Question 1151524
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The outer dimensions of your construction are  1 + 3 + 1 = 5 ft  and  1 + 7 + 1 = 9 ft,


so the full area is  5*9 = 45 square feet.


To answer the question, subtract from it the area of the garden itself, and you will get 

    
      45 - 3*7 = 45 - 21 = 24 square feet.    <U>ANSWER</U>
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