A cuboid has 3 quartets of parallel lines. Each quartet gives rise to six pairs. So, in all there are 18 pairs of parallel lines.
I'm pretty sure it is 12 pairs of parallel lines.
A rhombus has 2 pairs of parallel lines.
A regular dodecagon has six pairs of parallel lines.
A regular octagon has four pairs of parallel lines.
A square has 2 pairs of equal opposite parallel lines
12
I'm pretty sure it is 12 pairs of parallel lines.
3 pairs
3 pairs
21
Three.
4
A cuboid has 6 faces, and each face has a pair of parallel faces. So, a cuboid has 3 pairs of parallel faces. Mathematically speaking, that's the tea, honey.
A cuboid has 3 pairs of parallel faces.
A diamond has two pairs of parallel lines.
A rhombus has 2 pairs of parallel lines.
A regular dodecagon has six pairs of parallel lines.