(cod: P-61-45-6) A company manufactures picture frames with rectangular borders, where the left/right widths measure \(a = 4 \, cm\) and the top/bottom widths measure \(b = 6 \, cm\), as illustrated in the figure. The company fixes the main area of the picture frame (to be occupied by the picture) at \(384 \, cm^2\).


Determine the smallest possible value for the area of the front part of the borders.