How do you find the surface area of a 3D figure?

Question

directrix · Answer

The formulas are different depending on what the 3-D figure is.

anonymous · Answer

I meant something like #2

directrix · Answer

Which one would you like to work first. (I finally got my old version of Word to open.)

directrix · Answer

Problem 2, okay.

anonymous · Answer

yea..

directrix · Answer

#2 is a rectangular solid. 

Surface Area = perimeter of base times the height + 2 times the base area
SA = (8 + 8+ 12 + 12) times 12 + 2 times (12 times 8)
SA = (40) * 12 + 2 (96)
SA = 80*12 + 192
SA = 672 square meters

Check the work.

directrix · Answer

Also, there are six rectangular faces. You can get their areas using length times width and then adding those to get the surface area of the rectangular solid.

I count two 12 by 8, two 12 by 12, and two 8 by 12 rectangles if you want to work the problem this way.

anonymous · Answer

thx

directrix · Answer

Sorry that I had technical difficultieees. Do you want to work another?

anonymous · Answer

oh sorry