The length of the following box is 36 cm. If we cut
the length into 3 parts as shown, the surface area will increase by 120 cm^{2}.
What is the volume of this box?

cm^{3}

When we cut the cube into 3 parts, we make 2 cuts,
thus revealing 4 cross sections. These 4 cross sections are a total of 120 cm^{2}.
Therefore, each cross section has an area of 120 ÷ 4 = 30. Since the base area
is 30, the volume of the box is 30 × 36 = 1080 cm^{3}.