Respuesta :

63 ft

the area of her floor is 144 (12 × 12)

the area of the rug is 81 (9 × 9)

144 - 81 = 63

Area of a square = side^2

In our problem,

One side of the larger square = 12ft

one side of the smaller square = 9ft

12ft^2 - 9ft^2

144ft^2 - 81ft^2 = 63ft^2

C is the correct answer choice.