A rectangular prism has 6 flat faces, 12 straight edges, and 8 pointed vertices. Click the buttons to check each one.
Looking at a delivery box straight on, you can usually only see about 3 faces and 9 edges. But even without turning it over, you know there's an identical hidden part on the other side. A rectangular prism has three pairs of opposite faces — top-bottom, front-back, side-side — so if you see 3 from the front, there's one more of matching size on the far side of each, adding up to 6 total.
Edges work the same way. Add the visible solid-line edges to the hidden dashed-line edges and you always get 12, and vertices always come to 8. A special rectangular prism whose width, depth, and height are all equal is called a cube — the number of faces, edges, and vertices stays the same, but the difference is that all six faces are congruent squares.
Click the buttons to turn faces, edges, and vertices on one at a time, and find where the hidden parts marked with dashed lines are tucked away.