Can you see any shapes with curved lines? Why not try drawing a picture using only straight lines. A triangle has 3 sides and 3 vertices (corners). A vertex is where two lines meet or join.

The other four faces are all triangles. The shapes with 8 vertices are the cube and the cuboid. The cube has 6 faces all the same, but the cuboid has different faces.

The shape of a structure affects how strong it is. Rectangles, arches, and triangles are the most common shapes used to build big structures. What happens when you push the side of a rectangle?