Respuesta :

Answer:

  (b)  64 sq. in.

Step-by-step explanation:

The shaded area is the difference between the overall area and the areas of the cutout corners.

The overall area is 10 in by 10 in, so is ...

  A = s² = (10 in)² = 100 in²

The area of the cutout at each of the four corners is ...

  A = s² = (3 in)² = 9 in²

So, the total area of the four cutouts is ...

  cutout area = 4 × 9 in² = 36 in²

The remaining area is then ...

  100 in² -36 in² = 64 in²