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
(n + 1)
24 faces. A 23-gon base, and 23 triangles.
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.