Answer:
lol I hate chemical but let me give some advice
Explanation:
Please go on Khan Academy or look at your notes and I promise you can figure out! Seriously, I am trying to be helpful not like the annoying teacher that says "figure it out"
The two dimensions of aluminum foil are given 13.72 cm and 8.63 cm respectively with mass 3.1 g.
The density of aluminum is
. It is defined as mass per unit volume thus, volume of aluminum can be calculated as follows:

Putting the values.

The volume of cuboid is
, the length and breadth are given, height can be calculated as follows;

Putting the values,

Or, approximately 9.7\times 10^{-3}cm
Therefore, thickness of aluminum foil is 