Find the surface area of a rectangle prism

Surface area

it is 6 rectangles

rectangle area=legnth times width

but yo have legnth width and height

how does we do this?

answer

recognize that the rectanles come in pairs

rectanels that are oposite each other have equal areas

so we have

top=bottom=legnth times width

front face=back face=legnth times height

R side face and L side face=width times height

since there are 2 of each

SA=2 (LW) + 2 (LH) + 2 (WH)

undistribute 2

SA=2 (LW+LH+WH)

tada

(note: L=legnth, W=width, H=height)

and give your answer in square units