How do you find the surface area of 3 stacked cubes?

Answer 1

If they are all the same size, the surface area is just the total surface area, which is 6 (faces) x edge x edge - that is the area of one face, (the length of one edge times itself as cubes have square faces) x the number of faces (6) x the number of cubes (3). Then subtract fom this the area not exposed, which is the top face of the bottom cube, top and bottom of the middle cube and bottom face of the top cube - so that's 4 faces. So the formula boils down to:

6 x 3 x edge x edge - 4 x edge x edge

... or ...

14 edge²

If they are different sizes:

1. Work out the total area of each cube.

2. Between the bottom and middle cube, take the smaller and that face is hidden on both cubes, so subtract twice this face.

3. Do the same for the top and middle cubes.