Surface area and volume of cells

A list gives the sides of six cube-shaped cells. You will work out the surface area and the volume of each, then the ratio of the two, and find the first cell whose ratio falls below 1 per µm. Then the program draws the ratios.

The idea. A cube of side $s$ has a surface area of $6s^2$ and a volume of $s^3$.

Your tasks.

1. Set areas to the surface area of each cell, in µm².
2. Set volumes to the volume of each cell, in µm³.
3. Set ratios to the area divided by the volume, for each cell.
4. Set first_below_one to the first side whose ratio is below 1.