Question

A shelf 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?

Answer 1

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