2018 AMC 8

Solution 1

We count unit squares in the middle, and small triangles, which gives 4 rectangles each with an area of . Thus, the answer is .

Solution 2

We can see here that there are total squares in the middle. We also see that the triangles that make the corners of the shape have an area half the squares' area. Then, we can easily find that each corner has an area of one square and there are corners so we add that to the original 9 squares to get .