A decagonal based pyramid will have 11 faces, 11 vertices and 20 edges
11 vertices (one more than the number of vertices in the base).
The question cannot be answered because it makes no sense. "Decagonal" is an adjective, not a noun and the answer will depend on whether the question is about a decagonal pyramid, a decagonal prism or decagonal bipyramid, or something else.
12 faces 20 vertices 30 edges
Not sure what a decagonal is. Since the question refers to faces, edges and vertices, it may be assumed that the object in question is 3-dimensional. A decagon certainly is not, so decagonal cannot be a mistaken name for a decagon.
A decagonal prism has 20 vertices: 10 at each end.
A decagonal prism has 20 vertices: 10 at each end.
20 vertices.
A decagonal based pyramid will have 11 faces, 11 vertices and 20 edges
11 vertices (one more than the number of vertices in the base).
The question cannot be answered because it makes no sense. "Decagonal" is an adjective, not a noun and the answer will depend on whether the question is about a decagonal pyramid, a decagonal prism or decagonal bipyramid, or something else.
Vertices: 20 Edges: 30 Faces: 12
By "corners", do you mean vertices or edges?
12 faces 20 vertices 30 edges
Edges = 30 Faces = 12 Vertices = 20
20 edges, 11 vertices (corners) and 11 faces.
11 faces and 11 corners (vertices).