A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges.
A parallelogram or trapezoid.No!A parallelogram or a trapezoid are polygons (2-dimensional). A polyhedron, or 3-dimensional object, with parallel congruent bases is a prism.A prism. To give it fuller description, an "n-gonal prism" where the "n-gon" refers to the 2-d name of the bases.
There are N triangles in a N-gon
There are 15 triangles in a 17-agon
There are 20
n + 2
0
3n edges.
A prism with an n-sided base will have 2n vertices, n + 2 faces, and 3n edges.
An icosahedron is a polyhedron with 20 faces. The number of vertices and edges is indeterminate because there are many possible configurations.Three examples:A pyramid with a 19-gon base: 20 vertices, 38 edges.A dipyramid with a decagon base: 12 vertices, 30 edges.A prism with 18-gon bases: 36 vertices, 54 edges.An icosahedron is a polyhedron with 20 faces. The number of vertices and edges is indeterminate because there are many possible configurations.Three examples:A pyramid with a 19-gon base: 20 vertices, 38 edges.A dipyramid with a decagon base: 12 vertices, 30 edges.A prism with 18-gon bases: 36 vertices, 54 edges.An icosahedron is a polyhedron with 20 faces. The number of vertices and edges is indeterminate because there are many possible configurations.Three examples:A pyramid with a 19-gon base: 20 vertices, 38 edges.A dipyramid with a decagon base: 12 vertices, 30 edges.A prism with 18-gon bases: 36 vertices, 54 edges.An icosahedron is a polyhedron with 20 faces. The number of vertices and edges is indeterminate because there are many possible configurations.Three examples:A pyramid with a 19-gon base: 20 vertices, 38 edges.A dipyramid with a decagon base: 12 vertices, 30 edges.A prism with 18-gon bases: 36 vertices, 54 edges.
3n. n for the n-gon at each end, making 2n; and n along the length.
A dodecahedron has 12 pentagonal faces. But a 12-faced polyhedron could also be a 11-gon based pyramid, or a decagonal prism, or a hexagonal dipyramid, or many other shapes.
It has 20 faces. The number of edges will depend on the exact configuration of the shape. For example, a icosahedron in the form of a prism, with 18-gons as bases, will have 54 edges. On the other hand a pyramid with a 19-gon base will have 38 edges. A bipyramid with a decagon base will have 30 edges. There are very many more possible shapes.
n + 1
24 faces. A 23-gon base, and 23 triangles.
(n + 1)
An icosahedron is named after the number of faces that it has. The number of vertices will depend on the exact configuration of the shape. For example, a icosahedron in the form of a prism, with 18-gons as bases, will have 36 vertices. A pyramid with a 19-gon base will have 20 vertices. A bipyramid with a decagon base will have 12 vertices. There are very many more possible shapes.