Weight calculation

Hi All

I am using excel 2002.

I cut alphabet letters out of MDF. I need to calculate the total weight of any letter.
I have a program that will give me the area of any shape. In the picture below I have started with the letter “A”. B7 is the over all area. D7 is the small triangle. G7 is the total area minus the triangle D7. H7 is the thickness and I7 is the total volume.

Now I am stuck.
The weight of my MDF I have set at is 850kg cubic meter. That’s set in A3.

I need the total weight of the letter in J7 to be in grams.
The idea is, I put in the areas and set the thickness and it gives me the total weight.

When I done this a while, back it worked out pretty near. But I am not getting it to work.
Regards
Roger