Ashelf will covered with veneer on all 6 sides. the shelf is 48 inches long, 12 inches wide and 1 inch thick. what is the surface area of the shelf?

So. hmmmm notice the first picture, that's a rectangular prism

is really just 6 rectangles stacked up to each other at the edges

now, notice the second picture, is a prism/shelf with a length of 48, width of 12 and height of 1

so, your shelf is really just 6 rectangles stacked up to each other at the edges

you have 2 rectangles of 48x1 on the sides
2 rectangles of 12x1 for the front and back
and 2 rectangles of 12x48, for the top and bottom

get the area of each of those rectangles, add them up, and that's the surface area of the shelf

)because it's going in order of the math sign