Red fruit eight-character grass-planting brick
△ABC is an isosceles right triangle, AB=a,
AC=BC= 2 2 a，
So S △ABC = 1 2 AC? BC= 1 2 × 2 a 2？ 2 a 2 = a 2 4，
The area of the mid

Red fruit eight-character grass-planting brick

△ABC is an isosceles right triangle, AB=a,

AC=BC= 2 2 a，

So S △ABC = 1 2 AC? BC= 1 2 × 2 a 2？ 2 a 2 = a 2 4，

The area of the middle square is: a 2,

Then the shaded area is: 4× A24+A2 = 2A2.

So the answer is: 2A2.

Red fruit eight-character grass-planting brick△ABC is an isosceles right triangle, AB=a,AC=BC= 2 2 a，So S △ABC = 1 2 AC? BC= 1 2 × 2 a 2？ 2 a 2 = a 2 4，The area of the mid