three circles in a rectangle

Let the radius of each circle be $r$ and the area of the rectangle be $2r \cdot 4r = 8r^2$ . Solving for $r^2$ using the given yellow area gives:

$8r^2 - 2(\pi r^2) = 32-8\pi \Rightarrow r^2 = 4.$

Thus the rectangle's area computes to $8(4) = \boxed{32}.$