A rectangular prism (cuboid) has six rectangular faces. Volume = length × width × height. Surface area = 2(lw + lh + wh) — two of each pair of opposite faces.
A cube is a special rectangular prism where all three dimensions are equal (l = w = h = s). Volume = s³. Surface area = 6s² (six identical square faces).
If you know the volume and two dimensions, you can find the third: missing dimension = volume ÷ (the other two multiplied).
Remember
Volume = l × w × h. Surface area = 2(lw + lh + wh). The "2" in surface area comes from having two of each face.
Real World
A shipping box — the volume tells you if your item fits inside, the surface area tells you how much wrapping paper you need.
Feeling ready?
Put this concept to work with a practice workout.