8
A 2D rectangle has no edges but has 4 boundaries, and a 3D rectangle is a rectangular prism and has 12 edges.
12
12
15 edges.
12
9 edges
Eight.
A triangular prism has 9 edges, 5 faces and 6 vertices
12 edges/ 8 vertices/ 6 faces
A hexagonal prism has 8 faces, 18 edges, and 12 vertices.
A triangular prism has 9 edges and 5 faces. It also has 6 vertices. A cube has 6 faces and 12 edges.
2 faces and 5 edges so 7