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# 3rd hard-ish question

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Let A be the surface area of a 16 units by 1unit by 1 unit rright, rectangular prism and let B be the surface area of a 8 units by 2 units by 1 unit right rectangular prism. What is I A-B I in square units?

Jun 16, 2019

#1
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A=16

B=8

so

16+8=24                            Caution I am not sure if I a supposed to do the stuff on the bottom so I would wait for a user just to make sure! Thanks for understanding. :)

then B which equals 8 so 8*2*1=16

16+16 = 32sq units   Jun 16, 2019
#3
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Thank you! but you found the volume, and you added.... so thx for trying! The question asks for the surface area and subtraction tho...

NoobGuest  Jun 17, 2019
#2
+3 A  is the surface area of a  16 units  by  1 unit  by  1 unit  right, rectangular prism.

In square units,   A   =   2(1)(1) + 2(1)(16) + 2(1)(16)   =   2 + 32 + 32   =   66

B  is the surface area of a  8 units  by  2 units  by  1 unit  right, rectangular prism.

In square units,   B   =   2(1)(2) + 2(1)(8) + 2(2)(8)   =   4+ 16 + 32   =   52

So....

| A - B |   =   | 66 square units  -  52 square units |   =   14 square units

Jun 16, 2019
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Yep! THX hectictar! and why is your username hectic-tar..... tar isn't very hectic in my experience...

NoobGuest  Jun 17, 2019
#5
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Hahaha!! In my experience, "hectic" is a very fitting adjective to describe tar  But there is another reason for my username. It is an anagram of what I wanted to be when I grew up.

hectictar  Jun 17, 2019
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hectictar: I actually knew quite some time ago that your "username" was a anagram of  what you wanted to become when you finished your school! I knew that from your beautiful drawings. You will make a great "Architect"!,

Jun 17, 2019
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$$\text{A} = 2(1\cdot 1) + 4(16\cdot 1) = 66 \text { square units}\\ \text{B} = 2(8\cdot 2) + 2(8\cdot 1) + 2(2\cdot 1) = 52 \text { square units}\\ |\text{A} - \text{B}| = 66 - 52 = 14\text{ square units}$$

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Jun 22, 2019