How do you do Surface Areas in Geometry?

There are multiply different equations. Each Geometric figure has it's own equation. Basically, you do what it tells you. You find the area of the surface using equations for 2-D figures. For example, something easy: a box. To find the surface area, find the area of each side and add them together. Since opposite sides are the same, you can use this formula:

(H*L*2)+(L*W*2)+(W*H*2)= Surface area, where W= width, L= length, and H=height
You multiply these variables together to get the area of the box's faces. The multiplication of 2 within each set of parentheses represents the opposite side of the box, so you can do 2 sides at once.

Now try a real example. A box has dimensions of 3*4*5. What is its surface area?
3*4=12 (one side) 12*2=24 (this represents the first side and the side opposite of it.
4*5=20 20*2=40
5*3=15 15*2=30

Now add up the areas.

24+30+40=94, so the surface area is 94.

Did you get all of that? If you didn't, just tell me and I'll repeat myself.