Surface Area Block Problem

Date: 08/05/97 at 22:32:19
From: Lilly Joseph
Subject: Block surface area problem

Dear Dr. Math,

This surface area problem was in my geometry book and I didn't 
understand how to solve it. Please explain it to me.
 
Problem: Cheese is aged in large blocks. A block with length of 
15 cm, width of 15 cm, and height of 30 cm is cut up by a 
distributor into dimensions of 15 cm x 7.5 cm x 3 cm slabs 
to sell to grocery stores. At a minimum, how much foil is needed 
to wrap all the slabs from the block?

Yours truly,
Lilly Joseph

Date: 08/13/97 at 16:05:48
From: Doctor Rob
Subject: Re: Surface area block problem

There will be 20 blocks of cheese, by volume: 

   15*15*30/(15*7.5*3) = 20.  

Each one will have two faces that are 15 by 7.5, two that are 15 by 3, 
and two that are 7.5 by 3.  Add up the areas of these six rectangles 
to get the surface area of one block. Multiply by 20 to get the total 
surface area.

-Doctor Rob,  The Math Forum
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