I looked at it as a whole figure which is easier. You could also look at each piece in which the rectangle is 3×2=6, the top triangles which are 1/2×3×3/2 × 2(two triangles) = 4.5, and the bottom triangles which are 1/2*2*1*2(two triangles) = 2. Then add them all. 6+4.5+2 = 12.5.