For example, the length, width and height of a cuboid are 7.5, 5 and 3 respectively.
Surface area: (7.5×5+7.5×3+5×3)×2= 150.
Volume: 7.5×5×3= 1 12.5.
The side length of a cube is 5.
Surface area: 5×5×6= 150.
Volume: 5×5×5= 125
This problem is similar to "a rectangle and a square with equal perimeter, and the square has a larger area".