The window is 12 ft long and is split into 4 parts, so each section as a length of 3 ft.
The area of a square is s^2. We have to squares, so the area of them are 2*3^2 = 18 ft^2.
The area of a circle is pi*r^2, but we have two quarter circles, so the area would be 2pi*r^3/4.. (pi*3^2)/2 = 9pi/2 or 14.1372 ft^2.
Add the two together to get 32.1372 ft^2
Or in terms of pi, 18 + 9pi/2