Sawing a 1.2-meter-long cuboid into three sections on average, the surface area will increase by 2.4 square decimeters. How many square decimeters is the original wood? World for help!

Sawing a 1.2-meter-long cuboid into three sections on average, the surface area will increase by 2.4 square decimeters. How many square decimeters is the original wood? World for help!

When sawing into 3 sections, the number of additional cross sections is
(3-1) × 2 = 4
What is the cross-sectional area
2.4 △ 4 = 0.6 square decimeter
1.2 m = 12 decimeters
It turns out that the volume of this wood is
12 × 0.6 = 7.2 M3