Geometry
You need to find the area of the square first.
8x8=64un^2
Then you must find the area for the four triangles.
8x6=42un^2
42un^2/2=21un^2
Then multiply this by four to find the area of all the triangles.
21un^2x4=84un^2
Then add the areas of the triangles and squares.
84un^2+64un^2=148un^2