What is the surface area formula for a rectangular solid?

Answer 1

You mean a rectangular prism? Like a block of LEGO?

Then you just need to work out the surface area of the four sides, which will be two pairs of identical rectangles.

So;

((L*W)+(W*D))*2

L

______|______

/ /|

/____________/ |-D

| | |

| | /

|____________|/ \

W